Patent Application
20220117117
This application is based upon and claims the benefit of priority of the prior Japanese Patent Application No. 2020-173136, filed on Oct. 14, 2020, the entire contents of which are incorporated herein by reference.
The embodiments discussed herein are related to an electronic apparatus and a method for controlling an electronic apparatus.
With an increase in power consumption of a heat generator such as a central processing unit (CPU) mounted in an electronic unit, an increase in the number of heat generators mounted per unit area, and so on, the case of cooling the electronic unit by using a water-cooling system instead of performing cooling by using an air-cooling system is increasing. For example, it is known that a supply amount of coolant is made appropriate by controlling, based on a flow rate or temperature of the coolant flowing inside an electronic unit, a valve that adjusts the flow rate of the coolant. It is known that, in order to omit a flowmeter that may cause a pressure loss or the like, a flow rate of coolant is calculated based on an amount of heat generated by a heat generator mounted in an electronic unit, a temperature of the heat generator, and a temperature of the coolant. It is known that a monitor flow passage is provided between a supply-side manifold and a discharge-side manifold respectively located at inlets and outlets of a plurality of electronic units and a supply amount of coolant to the plurality of electronic units is made appropriate by adjusting a flow rate of the coolant that flows through this flow passage.
Japanese Laid-open Patent Publication No. 2005-228216, Japanese Laid-open Patent Publication No. 2015-79843, and Japanese Laid-open Patent Publication No. 2018-125497 are disclosed as related art.
According to an aspect of the embodiments, an electronic apparatus includes: a plurality of electronic units of two or more kinds, that are housed in a rack and that have respective internal flow passages through which coolant flows; a first pipe that is supplied with the coolant to flow through the internal flow passages of the plurality of electronic units; a second pipe in which the coolant discharged from the plurality of electronic units joins together; a plurality of distribution pipes that distribute the coolant from the first pipe to the plurality of electronic units; a plurality of discharge pipes that allow the coolant discharged from the plurality of electronic units to join together in the second pipe; a plurality of flow rate adjusting mechanisms that adjust flow rates of the coolant that flows into the plurality of distribution pipes from the first pipe; and a flow rate control unit that controls the plurality of flow rate adjusting mechanisms, wherein the flow rate control unit controls the plurality of flow rate adjusting mechanisms, based on desired flow rates of the coolant for the plurality of electronic units and information that indicates relationships between pressure losses and flow rates in a plurality of routes that include the internal flow passages of the plurality of electronic units, the plurality of distribution pipes, the plurality of discharge pipes, and the plurality of flow rate adjusting mechanisms and in which the coolant flows between the first pipe and the second pipe.
The object and advantages of the invention will be realized and attained by means of the elements and combinations particularly pointed out in the claims.
It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are not restrictive of the invention.
A plurality of electronic circuits of two or more kinds may be housed in a single rack. The electronic circuits of different kinds have different amounts of heat generated by heat generators and thus have different desired flow rates of coolant. The electronic circuits of different kinds have different heat generator arrangement layouts. Thus, water-cooling modules that constitute internal flow passages through which the coolant flows have different shapes and/or structures. Thus, the internal flow passages have different pressure losses.
There may be a case where when the coolant is distributed to the plurality of electronic circuits from a main pipe supplied with the coolant, the coolant flows in a concentrated manner through an electronic circuit whose internal flow passage has a smaller pressure loss and does not flow through the other electronic circuits at desired flow rates.
In one aspect, even in the case where a plurality of electronic circuits of two or more kinds are housed in a rack, coolant may flow through the plurality of electronic circuits at desired flow rates.
Embodiments of the present disclosure will be described below with reference to the drawings.
The cooling unit 60 is, for example, a coolant distribution unit (CDU) and includes a heat exchanger 61, a pump 62, and a flowmeter 63. The heat exchanger 61 is a device that performs heat exchange between primary refrigerant and secondary refrigerant. The primary refrigerant is supplied from a chiller (not illustrated) or a radiator (not illustrated) through a pipe 64a and is returned to the chiller or the radiator through a pipe 64b. In the heat exchanger 61, for example, heat exchange is performed between the primary refrigerant and the secondary refrigerant that are liquid.
The pump 62 is provided between the heat exchanger 61 and a coolant discharge port 65 of the cooling unit 60 on the downstream side of the heat exchanger 61 in a flow passage of the coolant (the secondary refrigerant). The pump 62 suctions and discharges the coolant cooled in the heat exchanger 61. The pump 62 may be a pump of a variable discharge flow rate type or a pump of a fixed discharge flow rate type. The pump 62 is, for example, an electric pump. The pump 62 has a capacity that enables the supply of the coolant to the plurality of electronic units 20a to 20d at a desired total flow rate.
The flowmeter 63 is provided between the heat exchanger 61 and a coolant receiving port 66 of the cooling unit 60. The flowmeter 63 measures the total flow rate of the coolant supplied to the electronic units 20a to 20d from the cooling unit 60. There may be a case where the flowmeter 63 is provided between the heat exchanger 61 and the coolant discharge port 65, for example, between the pump 62 and the coolant discharge port 65.
The rack 10 is equipped with a main pipe 30 (first pipe) through which the coolant supplied from the cooling unit 60 flows and with a main pipe 31 (second pipe) through which the coolant discharged from the electronic units 20a to 20d joins together. The main pipes 30 and 31 are metal pipes made of, for example, copper, stainless steel, or the like. The main pipe 30 is coupled to the coolant discharge port 65 of the cooling unit 60 by a coupling pipe 67. The main pipe 31 is coupled to the coolant receiving port 66 of the cooling unit 60 by a coupling pipe 68. The main pipes 30 and 31 and the coupling pipes 67 and 68 form a flow passage through which the coolant flows.
The main pipe 30 and the plurality of electronic units 20a to 20d are coupled to each other by a plurality of distribution pipes 40a to 40d, respectively. Thus, the coolant is distributed from the main pipe 30 to the plurality of electronic units 20a to 20d. The main pipe 31 and the plurality of electronic units 20a to 20d are coupled to each other by a plurality of discharge pipes 41a to 41d, respectively. Thus, the coolant discharged from the plurality of electronic units 20a to 20d joins together in the main pipe 31. The distribution pipes 40a to 40d and the discharge pipes 41a to 41d are, for example, hoses with couplers and form the flow passage through which the coolant flows. The distribution pipes 40a to 40d may be referred to as distribution pipes 40 when being collectively expressed. The discharge pipes 41a to 41d may be referred to as discharge pipes 41 when being collectively expressed.
The coolant supplied to the main pipe 30 from the cooling unit 60 is distributed to the electronic units 20a to 20d by the distribution pipes 40a to 40d, respectively. The coolant discharged from the electronic units 20a to 20d joins together in the main pipe 31 by the discharge pipes 41a to 41d, respectively. The coolant that has joined together in the main pipe 31 returns to the cooling unit 60. In this way, the coolant circulates between the cooling unit 60 and the electronic units 20a to 20d.
As illustrated in
In
As illustrated in
A route for the coolant that flows from the main pipe 30 to the main pipe 31 through the valve 50a, the distribution pipe 40a, the internal flow passage 23 of the electronic unit 20a, and the discharge pipe 41a is referred to as a route 1. Likewise, a route for the coolant that flows from the main pipe 30 to the main pipe 31 through the valve 50b, the distribution pipe 40b, the internal flow passage 23 of the electronic unit 20b, and the discharge pipe 41b is referred to as a route 2. A route for the coolant that flows from the main pipe 30 to the main pipe 31 through the valve 50c, the distribution pipe 40c, the internal flow passage 23 of the electronic unit 20c, and the discharge pipe 41c is referred to as a route 3. A route for the coolant that flows from the main pipe 30 to the main pipe 31 through the valve 50d, the distribution pipe 40d, the internal flow passage 23 of the electronic unit 20d, and the discharge pipe 41d is referred to as a route 4. Therefore, the routes 1 to 4 are coupled in parallel to each other between the main pipe 30 and the main pipe 31.
A case is assumed where all of the electronic units 20a to 20d in the electronic apparatus 500 according to the comparative example are electronic units of the same kind (specification) configured in the same manner to implement the same function. In this case, the electronic units 20a to 20d have the same amount of heat generated by the heat generators 22, and the water-cooling modules 24 through which the coolant for cooling the heat generators 22 flows have the same shape and structure. Therefore, the electronic units 20a to 20d have the same desired flow rate of the coolant and have the same pressure loss in the internal flow passages 23. In this case, the coolant supplied from the cooling unit 60 to the main pipe 30 is equally distributed to the electronic units 20a to 20d if the pressure losses in the distribution pipes 40a to 40d are equal to each other and the pressure losses in the discharge pipes 41a to 41d are equal to each other. Thus, by supplying the coolant from the cooling unit 60 to the main pipe 30 at a desired total flow rate for the electronic units 20a to 20d, the coolant is supplied to each of the electronic units 20a to 20d at the desired flow rate. For example, in the case where the desired flow rate of the coolant per electronic unit is Q [L/min], if the coolant is supplied from the cooling unit 60 at 4Q [L/min], the coolant is supplied to each of the electronic units 20a to 20d at Q [L/min].
However, electronic units, of two or more kinds of specifications, that implement different functions may be housed in the rack 10. A case is assumed where the electronic units 20a, 20b, and 20c are electronic units of the same kind and the electronic unit 20d is an electronic unit of a kind different from the kind of the electronic unit 20a, 20b, and 20c in the electronic apparatus 500 according to the comparative example. In this case, the amount of heat generated by the heat generator 22 is different between each of the electronic units 20a to 20c and the electronic unit 20d. Thus, the desired flow rate of the coolant for each of the electronic units 20a to 20c is different from the desired flow rate of the coolant fbr the electronic unit 20d. The arrangement layout of the heat generator 22 is different between each of the electronic units 20a to 20c and the electronic unit 20d. Thus, the shapes and/or structures of the water-cooling modules 24 are different and the pressure losses in the internal flow passages 23 are different. A case is assumed where the pressure loss in the internal flow passage 23 of the electronic unit 20d is smaller than the pressure loss in the internal flow passages 23 of each of the electronic units 20a to 20c. In this case, even if the coolant is supplied from the cooling unit 60 to the main pipe 30 at the desired total flow rate for the electronic units 20a to 20d, the coolant flows in a concentrated manner through the electronic unit 20d whose internal flow passage 23 has a smaller pressure loss. As a result, the coolant may not flow through each of the electronic units 20a to 20c at the desired flow rate. If a pump having a high supply capacity is used as the pump 62 of the cooling unit 60 so that the coolant flows also in each of the electronic units 20a to 20c at the desired flow rate, the power consumption of the cooling unit 60 increases.
Accordingly, description will be given below of a method for causing the coolant to flow through the electronic units 20a to 20d at the desired flow rates without increasing the supply capacity of the pump 62 even in the case where the electronic units 20a to 20d of two or more kinds are housed in the rack 10.
Tables 1 to 4 are examples of information stored in the storage unit 72. Table 1 is an example of characteristic information on electronic units mounted in the rack 10. As illustrated in Table 1, the storage unit 72 stores, as the characteristic information on the electronic units, the kind of each electronic unit, the desired flow rate of the coolant for the electronic unit, and information on P-Q characteristics indicating a relationship between the pressure loss and the flow rate in the internal flow passage of the electronic unit. As described above, when the kinds of the electronic units are different such as A to X, the desired flow rates of the coolant for the electronic units are different such as QA to QX. It is commonly known that the P-Q characteristics (pressure loss-flow rate characteristics) indicating the relationship between the pressure loss and the flow rate is approximated by ΔP=αQβ (where α and β are coefficients) in the case where ΔP denotes the pressure loss and Q denotes the flow rate. The coefficients α and β change depending on the kind of the coolant and/or the shape and structure of the water-cooling module 24 illustrated in
Table 2 illustrates an example of characteristic information on distribution pipes and discharge pipes. As illustrated in Table 2, the storage unit 72 stores, as the characteristic information on the distribution pipes and the discharge pipes, the kind of the pipe (for example, the kind of the hose) and information on P-Q characteristics indicating a relationship between the pressure loss and the flow rate in the pipe. Also for the distribution pipes and the discharge pipes, the coefficients α and β of the P-Q characteristics change depending on the shape and/or structure of the pipe. Thus, the coefficients α and β of the P-Q characteristics are stored as the information on the P-Q characteristics. In Table 2, a pressure loss ΔPH when the coolant flows through a pipe I at a flow rate QA is denoted by ΔPH=α1QA{circumflex over ( )}β1. The same applies to the other pipes.
Table 3 is an example of characteristic information on valves. As illustrated in Table 3, the storage unit 72 stores, as the characteristic information on the valves, information on P-Q characteristics indicating a relationship between the pressure loss and the flow rate in the valve, for each flow rate of the coolant that flows through the valve. When the opening degree of the valve is decreased, the flow passage narrows. Thus, when a parameter indicating the opening degree of the valve is denoted by k (for example, an open/close angle or an open/close rate), a pressure loss ΔPV in the valve is denoted by ΔPV=αV(k)Q{circumflex over ( )}(βV(k)) (where αV(k) and βV(k) are coefficients and functions of the opening degree k). For example, when the coolant flows at a desired flow rate QA for cooling an electronic unit A, the pressure loss ΔPV in the valve is denoted by ΔPV=αV(k)QA{circumflex over ( )}(βV(k)). Since the flow rate QA is fixed, the above equation may be represented by a simple equation with which the pressure loss is determined according to the opening degree of the valve using the variable k. It is commonly known that the pressure loss ΔPV in a valve when a flow rate is fixed is represented by ΔPV=γkδ (where γ and δ are coefficients and k denotes the opening degree of the valve). Therefore, as the information on the P-Q characteristics of the valve, the coefficients γ and δ are stored for each flow rate of the coolant that flows through the valve. For example, in Table 3, the pressure loss ΔPV when the coolant flows through the valve at the flow rate QA is denoted by ΔPV=γAk{circumflex over ( )}δA. The pressure loss ΔPV changes by changing the opening degree k of the valve. The same applies to other flow rates.
The information in Tables 1 to 3 is input to the storage unit 72 from the PC 90 after the information is obtained in advance from design information or the like or after evaluation and measurement are performed in advance by using a commonly known method. Table 3 illustrates the information on the P-Q characteristics in the case where the number of kinds of valves is one. However, in the case where there are a plurality of kinds of valves, information as illustrated in Table 3 may be stored for each of the kinds of valves.
Table 4 illustrates an example of information on the mounted positions of the electronic units in the rack 10 and the kinds of the electronic units mounted at the respective mounted positions. As illustrated in Table 4, the kind of the mounted electronic unit is stored for each of the mounted positions in the rack 10. The information illustrated in Table 4 is input to the storage unit 72 from the PC 90 when the kind and the mounted position of an electronic unit to be mounted in the rack 10 are determined.
The flow rate control unit 71 identifies, from among the routes 1 to 4, a first route with the largest sum among the sums of the pressure losses in the internal flow passages 23 of the electronic units 20a to 20d, the pressure losses in the distribution pipes 40a to 40d, and the pressure losses in the discharge pipes 41a to 41d, respectively (step S12).
The first route is identified based on Table 1, Table 2, and Table 4 stored in the storage unit 72. In the following description, it is assumed that the electronic units 20a, 20b, 20c, and 20d in the routes 1, 2, 3, and 4 are referred to as electronic units A, B, C, and D, respectively, and that all of the distribution pipes 40a to 40d and of the discharge pipes 41a to 41d are referred to as pipes I. In this case, the flow rate control unit 71 calculates a pressure loss ΔPSa in the internal flow passage 23 of the electronic unit 20a as ΔPSa=αAQA{circumflex over ( )}βA. Likewise, the flow rate control unit 71 calculates pressure losses ΔPSb to ΔPSd in the internal flow passages 23 of the electronic units 20b to 20d as ΔPSb=αBQB{circumflex over ( )}βB, ΔPSc=αCQC{circumflex over ( )}βC, and ΔPSd=αDQD{circumflex over ( )}βBD, respectively. The flow rate control unit 71 calculates a pressure loss ΔPHa in each of the distribution pipe 40a and the discharge pipe 41a as ΔPHa=αIQA{circumflex over ( )}βI. Likewise, the flow rate control unit 71 calculates a pressure loss ΔPHb in each of the distribution pipe 40b and the discharge pipe 41b as ΔPHb=αIQB{circumflex over ( )}βI. The flow rate control unit 71 calculates a pressure loss ΔPHc in each of the distribution pipe 40c and the discharge pipe 41c as ΔPHc=αIQC{circumflex over ( )}βI. The flow rate control unit 71 calculates a pressure loss ΔPHd in each of the distribution pipe 40d and the discharge pipe 41d as ΔPHd=αIQD{circumflex over ( )}βI. Based on the calculation results of these pressure losses, the flow rate control unit 71 identifies, as a first route, from among the routes 1 to 4, a route with the largest sum among sums of the pressure losses in the internal flow passages 23 of the electronic units 20a to 20d, the pressure losses in the distribution pipes 40a to 40d, and the pressure losses in the discharge pipes 41a to 41d, respectively.
The flow rate control unit 71 changes the opening degree of the valve located in the first route identified in step S12 to a certain value kA that is larger than the initial value (step S14). For example, in the case where the first route is the route 1, the flow rate control unit 71 changes the opening degree of the valve 50a located in the route 1 to 80%. The case is preferable where the certain value of the opening degree of the valve is not 100% but a value smaller than 100%, for example, 70% to 90%. This is for leaving room for increasing the opening degree to identify an abnormal route described in a second embodiment.
The flow rate control unit 71 calculates a total pressure loss ΔP1 of the pressure loss in the internal flow passage of the electronic unit, the pressure loss in the distribution pipe, the pressure loss in the discharge pipe, and the pressure loss in the valve in the first mute (step S16). The total pressure loss ΔP1 in the first route is calculated based on Tables 1 to 4. For example, it is assumed that the first route is the route 1 and the opening degree of the valve 50a located in the route 1 is 80%. In this case, the pressure loss ΔPSa in the internal flow passage 23 of the electronic unit 20a located in the route 1 is calculated as ΔPSa=αAQA{circumflex over ( )}βA, and the pressure loss ΔPHa in each of the distribution pipe 40a and the discharge pipe 41a located in the route 1 is calculated as ΔPHa=αIQA{circumflex over ( )}BI. A pressure loss ΔPVa in the valve 50a located in the route 1 is calculated as ΔPVa=γAk80{circumflex over ( )}δA. Therefore, the flow rate control unit 71 calculates, as the total pressure loss ΔP1 in the route 1, ΔP1=ΔPSa+2ΔPHa+ΔPVa. The pressure loss ΔPSa in the internal flow passage 23 of the electronic unit 20a and the pressure loss ΔPHa in each of the distribution pipe 40a and the discharge pipe 41a are constants. The pressure loss ΔPVa in the valve 50a is also a constant since the opening degree of the valve 50a is fixed. Therefore, ΔP1 is A (constant).
The flow rate control unit 71 calculates the opening degree of the valve located in each of the remaining routes other than the first route such that the total pressure loss in the remaining route is equal to the total pressure loss in the first route (step S18). For example, a total pressure loss ΔP2 in the route 2 is calculated as ΔP2=ΔPSb+2ΔPHb+ΔPVb. ΔPSb is calculated as ΔPSb=αBQB{circumflex over ( )}βB, ΔPHb is calculated as ΔPHb=αIQB{circumflex over ( )}βI, and ΔPVb is calculated as ΔPVb=γBkB{circumflex over ( )}δB. Since the pressure loss ΔPSb in the internal flow passage 23 of the electronic unit 20b and the pressure loss ΔPHb in each of the distribution pipe 40b and the discharge pipe 41b are constants, ΔP2 is βP2=γBkB{circumflex over ( )}δB+B (constant). Therefore, in order for ΔP1 and ΔP2 to be equal to each other, A (constant)=γBkB{circumflex over ( )}δB+B (constant) is to be satisfied. Thus, an opening degree kB of the valve 50b is calculated as in Equation 1 below.
Likewise, a total pressure loss ΔP3 in the route 3 is calculated as ΔP3=ΔPSc+2ΔPHc+ΔPVc. ΔPSc is calculated as ΔPSc=αCQC{circumflex over ( )}βC, ΔPHc is calculated as ΔPHc=αIQI{circumflex over ( )}βI, and ΔPVc is calculated as ΔPVc=γCkC{circumflex over ( )}δC. Since the pressure loss ΔPSc in the internal flow passage 23 of the electronic unit 20c and the pressure loss ΔPHc in each of the distribution pipe 40c and the discharge pipe 41c are constants, ΔP3 is ΔP3=γCkC{circumflex over ( )}δC+C (constant). Therefore, in order for ΔP1 and ΔP3 to be equal to each other, A (constant)=γCkC{circumflex over ( )}δC+C (constant) is to be satisfied. Thus, an opening degree kC of the valve 50c is calculated as in Equation 2 below.
A total pressure loss ΔP4 in the route 4 is calculated as ΔP4=ΔPSd+2ΔPHd+ΔPVd. ΔPSd is calculated as ΔPSd=αDQD{circumflex over ( )}βD, ΔPHd is calculated as ΔPHd=α1Q1{circumflex over ( )}β1, and ΔPVd is calculated as ΔPVd=γDkD{circumflex over ( )}δD. Since the pressure loss ΔPSd in the internal flow passage 23 of the electronic unit 20d and the pressure loss ΔPHd in each of the distribution pipe 40d and the discharge pipe 41d are constants, ΔP4 is ΔP4=γDkD{circumflex over ( )}δD+D (constant). Therefore, in order for ΔP1 and ΔP4 to be equal to each other, A (constant)=γDkD{circumflex over ( )}δD+D (constant) is to be satisfied. Thus, an opening degree kD of the valve 50d is calculated as in Equation 3 below.
The flow rate control unit 71 changes the opening degrees of the valves located in the remaining routes to the respective opening degrees of the valves calculated in step S18 (step S20). Thus, as a result of supplying the coolant from the cooling unit 60 to the main pipe 30 at the desired total flow rate for the electronic units 20a to 20d, the coolant is supplied the electronic units 20a to 20d located in the routes 1 to 4 at the desired flow rates.
The flow rate determination unit 73 compares a supply flow rate of the coolant, which is obtained by receiving the detection signal of the flowmeter 63 of the cooling unit 60, with the desired total flow rate of the coolant for the electronic units 20a to 20d, and determines whether a difference therebetween is within a certain range (step S22). The difference between the supply flow rate and the desired total flow rate being within the certain range may be, for example, the difference between the supply flow rate and the desired total flow rate being within ±5%, ±3%, or ±2% of the desired total flow rate. If the flow rate determination unit 73 determines that the difference between the flow rates is within the certain range (Yes), the flow rate determination unit 73 determines that the coolant is supplied to the electronic units 20a to 20d at desirable flow rates and powers on the electronic units 20a to 20d (causes the electronic units 20a to 20d to transition from a standby state to an operating state) (step S24). The process then ends. On the other hand, if the flow rate determination unit 73 determines that the difference between the flow rates is out of the certain range (No), the flow rate determination unit 73 determines that something is wrong with the input information and ends the process without powering on the electronic units 20a to 20d. When the process ends without power-on, for example, an alarm may be issued, or a message indicating that the information input to the storage unit 72 is wrong may be displayed on the PC 90.
According to the first embodiment, the plurality of valves 50a to 50d are controlled based on the desired flow rates of the coolant for the plurality of electronic units 20a to 20d and the information indicating the relationships between the pressure losses and the flow rates in the plurality of routes 1 to 4. Thus, the coolant may be distributed from the main pipe 30 to the plurality of routes 1 to 4 at the desired flow rates for the electronic units 20a to 20d, and the coolant may be caused to flow through the electronic units 20a to 20d at the desired flow rates. For example, even when the electronic units 20a to 20d of a plurality of kinds are housed in the single rack 10, a situation in which the coolant flows through a certain electronic unit in a concentrated manner is avoided and the occurrence of an electronic unit in which the flow rate of the coolant is insufficient is avoided. As a result of housing of the electronic units 20a to 20d of the plurality of kinds in the single rack 10 being enabled, increases in the number of racks 10 and in the number of cooling units 60 are avoided. The information on the desired flow rates of the coolant for the electronic units and the information indicating the relationships between the pressure losses and the flow rates are obtained in advance, and, by using these pieces of information, the coolant is caused to flow at the desired flow rates for the electronic units. Thus, the use of a temperature monitor and/or a flow rate monitor may be omitted. Consequently, a complicated mechanism for performing monitoring in real time by communication or the like may be avoided and high-density mounting of the electronic units may be enabled.
As in S16 to S20 in
The pressure losses in the routes 1 to 4 are preferably the sums of the pressure losses in the internal flow passages 23 of the electronic units 20a to 20d, the pressure losses in the distribution pipes 40a to 40d, the pressure losses in the discharge pipes 41a to 41d, and the pressure losses in the valves 50a to 50d, respectively. This is because the pressure losses in the internal flow passages 23, the distribution pipes 40a to 40d, the discharge pipes 41a to 41d, and the valves 50a to 50d greatly affect the ease-of-flow of the coolant.
As in S12 to S20 in
As in S22 of
In the first embodiment, the case where the information on the desired flow rates of the coolant for the electronic units, the information indicating the relationships between the pressure loss and the flow rate in the routes, and the information on the mounted positions of the electronic units in the rack are stored in the storage unit 72 has been described by way of example. However, the configuration is not limited to the case where these pieces of information are stored in the storage unit 72 included in the control unit 70, and the pieces of information may be stored in an external storage medium of the control unit 70 and may be read for use from this storage medium.
In the case where coolant is supplied to the electronic units 20a to 20d, clogging may occur in a flow passage through which the coolant flows because of deposition of fine dust, precipitation of a foreign matter due to chemical reaction, propagation of bacteria, peeling of a component, and/or the like. For example, as illustrated in
The flow rate determination unit 73 determines whether a difference between the supply flow rate of the coolant to the main pipe 30 immediately after the flow rate of the coolant is adjusted (the supply flow rate of the coolant obtained in step S22 of
If the difference between the supply flow rate immediately after the flow rate adjustment and the latest supply flow rate is within the first specified range (No), the process returns to step S30. On the other hand, if the difference between the supply flow rate immediately after the flow rate adjustment and the latest supply flow rate is out of the first specified range (Yes), the process proceeds to step S34. In step S34, the flow rate control unit 71 calculates the opening degrees of the valves 50a to 50d with which the flow rate of the coolant supplied to the main pipe 30 increases by a certain flow rate, and changes the opening degrees of the valves 50a to 50d to the calculated opening degrees in turn. Each time the opening degrees of the valves 50a to 50d are changed in turn, the identification unit 76 obtains, based on the detection signal of the flowmeter 63 of the cooling unit 60, the supply flow rate of the coolant supplied from the cooling unit 60 to the main pipe 30.
For example, the flow rate control unit 71 calculates the opening degree of the valve 50a with which the flow rate of the coolant supplied to the main pipe 30 (the total flow rate of the coolant that flows through the routes 1 to 4) increases by a certain flow rate (first flow rate). The flow rate control unit 71 increases the opening degree of the valve 50a located in the route 1 to the calculated opening degree. The opening degree of the valve 50a for causing the flow rate of the coolant supplied to the main pipe 30 to increase by the certain flow rate (first flow rate) is calculated by using the following method. In the following description, a case where the flow rate of the coolant supplied to the main pipe 30 increases by 3 [1/min] will be described by way of example. The opening degree of the valve 50a located in the route 1 is increased from kA to kA′. KA′ may be appropriately set. Suppose that the flow rate of the coolant that flows through the route 1 at this time is denoted by QA′. In such a case, a pressure loss ΔP1′ in the route 1 is calculated as ΔP1′=αAQA′{circumflex over ( )}βA+2αAQA′{circumflex over ( )}βI+α(kA′)QA′{circumflex over ( )}(kA′).
As a result of the opening degree of the valve 50a in the route 1 being changed, the condition that all the pressure losses in the routes 1 to 4 are equal to each other collapses. Thus, the flow rates of the coolant that flows through the routes 2 to 4 also change. For example, as a result of an increase in the amount of the coolant that flows through the route 1 in response to an increase in the opening degree of the valve 50a, the flow rates of the coolant that flows through the routes 2 to 4 slightly decrease. Pressure losses ΔP2′ to ΔP4′ in the routes 2 to 4 at this time are calculated as follows: ΔP2′=αBQB′{circumflex over ( )}βB+2αBQB′{circumflex over ( )}βI+α(kB)QB′{circumflex over ( )}β(kB); ΔP3′=αCQC′ {circumflex over ( )}βC+2αIQC′{circumflex over ( )}βI+α(kC)QC′{circumflex over ( )}β(kC); and ΔP4′=αDQD′{circumflex over ( )}βD+2αIQD′{circumflex over ( )}βI+α(kD)QD′{circumflex over ( )}β(kD), where KB, kC, and kD are values determined in the flowchart of
In the aforementioned ΔP1′ to ΔP4′, QA′ to QD′ that satisfy ΔP1′=ΔP2′=ΔP3′=ΔP4′ are calculated, and a total flow rate value Q′ (Q′=QA′+QB′+QC′+QD′) of QA′ to QD′ is calculated. The total flow rate value Q′ is compared with a total flow rate value Q (Q=QA+QB+QC+QD) of the flow rates QA to QD of the coolant that flows through the routes 1 to 4 when the opening degrees of the valves 50a to 50d in the routes 1 to 4 are kA to kD, respectively, and the pressure losses in the routes 1 to 4 are equal to each other. If the total flow rate value Q′ increases from the total flow rate value Q by 3 [L/min], it is determined that the opening degree of the valve 50a located in the route 1 is to be kA′. If the total flow rate value Q increases or decreases from the total flow rate value Q by an amount other than 3 [L/min], the opening degree of the valve 50a located in the route 1 is changed from kA′ and recalculation is performed. The similar operation is performed for the valves 50b to 50d in the routes 2 to 4, and the opening degrees kB′, kC′, and kD′ in the case where the total flow rate value when the opening degrees of the valves 50b to 50d are changed increases from the total flow rate value Q by 3 [L/min] are determined by calculation, respectively.
Thus, in step S34, the flow rate control unit 71 increases the opening degree of the valve 50a located in the route 1 to the opening degree calculated such that the coolant supplied to the main pipe 30 increases by the certain flow rate (first flow rate). The opening degrees of the valves 50b to 50d respectively located in the routes 2 to 4 are not changed. The identification unit 76 obtains, based on the detection signal of the flowmeter 63, the supply flow rate of the coolant supplied from the cooling unit 60 to the main pipe 30 when the opening degree of the valve 50a located in the route 1 is increased. The flow rate control unit 71 returns the opening degree of the valve 50a located in the route 1 to the original state.
The flow rate control unit 71 increases the opening degree of the valve 50b located in the route 2 to the opening degree calculated such that the flow rate of the coolant supplied to the main pipe 30 increases by the certain flow rate (first flow rate). The opening degrees of the valves 50a, 50c, and 50d respectively located in the routes 1, 3, and 4 are not changed. The opening degree of the valve 50b is calculated by using the same method as that for the opening degree of the valve 50a in the route 1 as described above. The identification unit 76 obtains, based on the detection signal of the flowmeter 63, the supply flow rate of the coolant supplied from the cooling unit 60 to the main pipe 30 when the opening degree of the valve 50b located in the route 2 is increased. The flow rate control unit 71 returns the opening degree of the valve 50b located in the route 2 to the original state.
The similar operation is performed for the routes 3 and 4. For example, the flow rate control unit 71 increases the opening degree of the valve 50c located in the route 3 to the opening degree calculated such that the flow rate of the coolant supplied to the main pipe 30 increases by the certain flow rate (first flow rate). The opening degrees of the valves 50a, 50b, and 50d respectively located in the routes 1, 2, and 4 are not changed. The opening degree of the valve 50c is calculated by using the same method as that for the opening degree of the valve 50a in the route 1 as described above. The identification unit 76 obtains, based on the detection signal of the flowmeter 63, the supply flow rate of the coolant supplied from the cooling unit 60 to the main pipe 30 when the opening degree of the valve 50c located in the route 3 is increased. The flow rate control unit 71 returns the opening degree of the valve 50c located in the route 3 to the original state. The flow rate control unit 71 increases the opening degree of the valve 50d located in the route 4 to the opening degree calculated such that the flow rate of the coolant supplied to the main pipe 30 increases by the certain flow rate (first flow rate). The opening degrees of the valves 50a to 50c respectively located in the routes 1 to 3 are not changed. The opening degree of the valve 50d is calculated by using the same method as that for the opening degree of the valve 50a in the route 1 as described above. The identification unit 76 obtains, based on the detection signal of the flowmeter 63, the supply flow rate of the coolant supplied from the cooling unit 60 to the main pipe 30 when the opening degree of the valve 50d located in the route 4 is increased. The flow rate control unit 71 returns the opening degree of the valve 50d located in the route 4 to the original state.
The identification unit 76 compares the supply flow rates, obtained in step S34, of the coolant supplied to the main pipe 30 with each other (step S36). For example, the identification unit 76 compares the supply flow rate obtained when the opening degree of the valve 50a located in the route 1 is increased with the supply flow rates obtained when the opening degrees of the valves 50b to 50d located in the routes 2 to 4 are increased, and obtains differences therebetween. The identification unit 76 compares the supply flow rate obtained when the opening degree of the valve 50b located in the route 2 is increased with the supply flow rates obtained when the opening degrees of the valves 50c and 50d located in the routes 3 and 4 are increased, and obtains differences therebetween. The identification unit 76 compares the supply flow rate obtained when the opening degree of the valve 50c located in the route 3 is increased with the supply flow rate obtained when the opening degree of the valve 50d located in the route 4 is increased, and obtains a difference therebetween.
For example, it is assumed that the supply flow rate of the coolant supplied to the main pipe 30, which is obtained based on the detection signal of the flowmeter 63 when Yes is determined in step S32, is 84 [L/min]. It is assumed that the opening degrees of the valves 50a to 50d are increased in turn so that the flow rate of the coolant supplied to the main pipe 30 increases each time by 3 [L/min] by calculation in step S34. In this case, it is assumed that the supply flow rate detected by the flowmeter 63 when the opening degree of the valve 50a in the route 1 is increased is 87 [L/min]. It is assumed that the supply flow rate detected by the flowmeter 63 when the opening degree of the valve 50b in the route 2 is increased is 86.9 [L/min]. It is assumed that the supply flow rate detected by the flowmeter 63 when the opening degree of the valve 50c in the route 3 is increased is 87.1 [L/min]. It is assumed that the supply flow rate detected by the flowmeter 63 when the opening degree of the valve 50d in the route 4 is increased is 86.1 [L/min].
In such a case, the difference in supply flow rate of the coolant supplied to the main pipe 30 between when the opening degree of the valve 50a located in the route 1 is increased and when the opening degree of the valve 50b located in the route 2 is increased is calculated to be 87-86.9=0.1 [L/min]. Likewise, the difference in supply flow rate between the route 1 and the route 3 is calculated to be −0.1 [L/min], and the difference in supply flow rate between the route 1 and the route 4 is calculated to be 0.9 [L/min]. The difference in supply flow rate between the route 2 and the route 3 is calculated to be −0.2 [L/min], the difference in supply flow rate between the route 2 and the route 4 is calculated to be 0.8 [1/min], and the difference in supply flow rate between the route 3 and the route 4 is calculated to be 1.0 [L/min].
The identification unit 76 determines whether there is a difference that is out of a second specified range among the differences in supply flow rates of the coolant supplied to the main pipe 30 that are compared in step S36 (step S38). The second specified range may be, for example, within 0.8 [L/min] but may be within 0.7 [L/min], 0.6 [L/min], or 0.5 [L/min]. The second specified range may be set such that the difference in supply flow rate of the coolant is within 0.8%, 0.6%, or 0.4% of the supply flow rate of the coolant before the opening degrees of the valves 50a to 50d are increased.
If there is a difference in supply flow rate of the coolant supplied to the main pipe 30 that is out of the second specified range in step S38 (Yes), the identification unit 76 identifies, based on the results of the differences in supply flow rate of the coolant, an abnormal route in which an abnormality such as flow passage clogging has occurred (step S40). The notification control unit 77 issues, from the notification unit 45, an alarm indicating the abnormal route in which the abnormality has occurred (step S42). For example, the case is assumed where the supply flow rates detected by the flowmeter 63 when the opening degrees of the valves 50a to 50d are increased in turn are as described above. In this case, the difference between the supply flow rate when the opening degree of the valve 50d located in the route 4 is increased and the supply flow rate when the opening degree of each of the valves 50a to 50c respectively located in the routes 1 to 3 is increased is out of the second specified range. Thus, the identification unit 76 identifies that an abnormality such as flow passage dogging has occurred in the route 4, and the notification control unit 77 issues an alarm.
On the other hand, if there is no difference in supply flow rate of the coolant supplied to the main pipe 30 that is out of the second specified range in step S38 (No), the notification control unit 77 issues, from the notification unit 45, an alarm indicating that an abnormality has occurred in the pump 62 (step S44). The process then ends. This is because it is considered that the reason why the difference in supply flow rate of the coolant supplied to the main pipe 30 is out of the first specified range in step S32 is not because of flow passage dogging or the like but because of an abnormality in the pump 62.
After step S42, the temperature determination unit 78 obtains the temperature of the heat generator 22 of the electronic unit located in the abnormal route, based on the detection signal of the thermometer 25 (see
On the other hand, if a temperature abnormality has occurred in the electronic unit (Yes in step S46), the flow rate control unit 71 closes the valve located in the abnormal route (step S48). Consequently, the coolant is no longer supplied to the abnormal route, and the electronic unit in the abnormal route may be powered off and replaced or the like.
The flow rate control unit 71 recalculates the opening degrees of the valves located in the remaining routes other than the abnormal route (step S50). In the recalculation of the opening degrees of the valves, the opening degrees of the valves are calculated with which the pressure losses in the remaining routes are made equal to each other, as in the method described in the flowchart of
According to the second embodiment, as in S32 to S40 in
As in steps S34 to S40 in
As in S48 to S52 in
In the case where the abnormal route is identified, an alarm indicating the identified abnormal route may be issued. Consequently, the route in which an abnormality has occurred may be easily recognized.
While the embodiments of the present disclosure have been described in detail above, the present disclosure is not limited to such specific embodiments, and various modifications and alterations may be made within the scope of the gist of the present disclosure described in the claims.
All examples and conditional language provided herein are intended for the pedagogical purposes of aiding the reader in understanding the invention and the concepts contributed by the inventor to further the art, and are not to be construed as limitations to such specifically recited examples and conditions, nor does the organization of such examples in the specification relate to a showing of the superiority and inferiority of the invention. Although one or more embodiments of the present invention have been described in detail, it should be understood that the various changes, substitutions, and alterations could be made hereto without departing from the spirit and scope of the invention.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2020-173136 | Oct 2020 | JP | national |
