This disclosure relates to pumps, for example, centrifugal pumps.
Centrifugal pumps increase the pressure of transported fluid by converting rotational kinetic energy into hydrodynamic energy. The energy is provided by an external engine or electrical motor.
Centrifugal pumps are efficient for their physical size making them useful in places with a limited footprint such as a ship, wellbore, or municipal water system.
This disclosure describes a centrifugal pump with adaptive pump stages.
An example implementation of the subject matter described within this disclosure is a pump with the following features. An impeller provides kinetic energy to flow fluid through the pump. The impeller has multiple geometric dimensions. A diffuser is connected to the impeller. The diffuser converts the kinetic energy provided by the impeller into static pressure energy to flow the fluid through the pump. An adaptive material is attached to the impeller. The adaptive material is capable of modifying, during operation of the pump, a geometric dimension of the multiple geometric dimensions in order to modify fluid flow through the pump.
Aspects of the example implementation, which can be combined with the example implementation alone or in combination, include the following. The geometric dimensions include an impeller outer diameter and an impeller blade trailing edge angle.
Aspects of the example implementation, which can be combined with the example implementation alone or in combination, include the following. The impeller includes an impeller blade having the impeller blade trailing edge angle. The adaptive material is configured to increase or decrease the impeller blade trailing edge angle during operation of the pump.
Aspects of the example implementation, which can be combined with the example implementation alone or in combination, include the following. A leading edge or a trailing edge of the impeller blade is made of the adaptive material.
Aspects of the example implementation, which can be combined with the example implementation alone or in combination, include the following. A trailing region of the impeller blade is made of the adaptive materials.
Aspects of the example implementation, which can be combined with the example implementation alone or in combination, include the following. The adaptive materials comprise properties configured to change in response to an external stimulus including at least one of stress, temperature, moisture, pH, electric field or magnetic field.
Aspects of the example implementation, which can be combined with the example implementation alone or in combination, include the following. The adaptive materials include a piezoelectric material, a magnetostrictive material, or a shape memory material configured to modify the geometric dimension in response to an outside stimulus.
Aspects of the example implementation, which can be combined with the example implementation alone or in combination, include the following. An electric charge source is connected to the impeller. The electric charge source provides the electric charge to modify the geometric dimension.
Aspects of the example implementation, which can be combined with the example implementation alone or in combination, include the following. A magnetic field source is connected to the impeller. The magnetic field source provides the magnetic field to modify the geometric dimension.
Aspects of the example implementation, which can be combined with the example implementation alone or in combination, include the following. A pump condition during the operation of the pump under which the adaptive materials modify the geometric dimension includes a pump temperature during the operation of the pump.
Aspects of the example implementation, which can be combined with the example implementation alone or in combination, include the following. The adaptive materials include at least one of pH-sensitive polymers, temperature-responsive polymers, magnetorheological fluids, electroactive polymers, or thermoelectric materials.
Aspects of the example implementation, which can be combined with the example implementation alone or in combination, include the following. The impeller is a first impeller, the diffuser is a first diffuser, the first impeller and the first diffuser form a first pump stage, wherein the pump further includes a second pump stage connected in series with the first pump stage. The second pump stage includes a second impeller that provides kinetic energy to flow fluid through the pump. The second impeller has multiple geometric dimensions. A second diffuser is connected to the second impeller. The second diffuser converts the kinetic energy provided by the second impeller into static pressure energy to flow the fluid through the pump.
Aspects of the example implementation, which can be combined with the example implementation alone or in combination, include the following. The second pump stage does not include adaptive materials.
Aspects of the example implementation, which can be combined with the example implementation alone or in combination, include the following. An adaptive material is attached to the diffuser. The adaptive material attached to the diffuser is configured to modify, during operation of the pump, a geometric dimension of the diffuser in order to modify fluid flow through the pump.
An example implementation of the subject matter described within this disclosure is a method with the following features. An adaptive material is attached to an impeller of a pump. The impeller provides kinetic energy to flow fluid through the pump. The impeller has multiple geometric dimensions. The adaptive material is configured to modify, during operation of the pump, a geometric dimension to modify fluid flow through the pump. Wherein the impeller is connected to a diffuser that converts the kinetic energy provided by the impeller into static pressure energy to flow the fluid through the pump. The adaptive material is actuated during the operation of the pump to modify the geometric dimension of the impeller.
Aspects of the example method, which can be combined with the example method alone or in combination, include the following. The geometric dimensions include an impeller outer diameter and an impeller blade trailing edge angle.
Aspects of the example method, which can be combined with the example method alone or in combination, include the following. The impeller includes an impeller blade having the impeller blade trailing edge angle. The adaptive material is configured to increase or decrease the impeller blade trailing edge angle during operation of the pump.
Aspects of the example method, which can be combined with the example method alone or in combination, include the following. The impeller includes an impeller blade with the impeller blade leading edge angle. The adaptive material is configured to increase or decrease the impeller blade leading edge angle during operation of the pump.
Aspects of the example method, which can be combined with the example method alone or in combination, include the following. The diffuser includes a diffuser blade having the diffuser blade trailing edge angle. The adaptive material is configured to increase or decrease the diffuser blade trailing edge angle during operation of the pump.
Aspects of the example method, which can be combined with the example method alone or in combination, include the following. The impeller includes a diffuser blade with the diffuser blade leading edge angle. The adaptive material is configured to increase or decrease the diffuser blade leading edge angle during operation of the pump.
Aspects of the example method, which can be combined with the example method alone or in combination, include the following. The adaptive materials include properties that change in response to temperature.
Aspects of the example method, which can be combined with the example method alone or in combination, include the following. The adaptive materials include properties that change in response to pump conditions during the operation of the pump.
Aspects of the example method, which can be combined with the example method alone or in combination, include the following. The adaptive materials include a piezoelectric material, a magnetostrictive material, or a shape memory material configured to modify the geometric dimension in response to an outside stimulus.
Aspects of the example method, which can be combined with the example method alone or in combination, include the following. The shape memory materials include at least one of pH-sensitive polymers, temperature-responsive polymers, magnetorheological fluids, electroactive polymers or thermoelectric materials.
Aspects of the example method, which can be combined with the example method alone or in combination, include the following. Actuating the adaptive material during the operation of the pump to modify the geometric dimension of the impeller includes applying an electric charge or magnetic field to the adaptive material to modify the geometric dimension.
Like reference symbols in the various drawings indicate like elements.
A centrifugal pump includes pump stages, each of which is defined as sections of a centrifugal pump consisting of one impeller that rotates and a diffuser with a set of stationary vanes downstream of the impeller. The fluid enters the inlet towards the center of the impeller and flows along the blades, where the fluid is accelerated radially outwards into the diffuser that transforms rotational energy into pressure. The impeller determines the pump performance. The speed and geometry of the impeller, that is, diameter, number and shape of the blades, and inlet and outlet width determine operating point, head, and efficiency. Pump variants are often created by slightly modifying the impeller geometry.
Centrifugal pumps are designed and sized for a narrow operating envelope. Examples of process parameters that are taken into account when designing a centrifugal pump include: flow rate, head, suction pressure, discharge pressure, viscosity, abrasive content, corrosiveness, power, specific gravity, and many others. If one of these parameters in a process changes significantly, then the pump operation has to be adjusted to match the current process conditions.
This disclosure describes a centrifugal pump with an adaptable pump stage which includes an adaptable impeller, an adaptable diffuser, or both. The adaptability of the pump stages can be achieved through adaptive materials that can either be self-actuated or actuated from an external stimulus. The adaptability allows the pump to have its pump curve adjusted to better fit changing process conditions including optimum power efficiency for a wider range of operation and better response to changes in fluid density.
Operating centrifugal pumps near the BEP 206 is preferable for a variety of reasons. As a pump moves away from the BEP 206, less of the kinetic energy imparted to the fluid is converted into hydraulic energy and more is converted into heat. This excess heat causes accelerated wear on the pump and will reduce the mean-time-between-failures (MTBF). On top of the heat generation, running the pump away from the BEP can cause cavitation, increased power requirements, increased thrust loads, increased radial loads, and can create vibration issues within the pump. All of these issues can reduce MTBF and increase operating costs.
The pump curve 302 is more level than pump curve 202, meaning that the adaptable pump is able to deliver a variety of flow-rates at a nearly constant head. In other words, operating the pump within the BER 306 allows the pump to deliver fluid at a constant head into a downstream process even if the flow varies at the pump suction. Such an ability is useful in oil production applications where flow rates vary and wells are known to slug. In addition, the performance map 300 has a wider efficiency curve than performance map 200, giving the pump a comparatively greater operable range without suffering the typical issues that cause a shortening in the pumps MTBF.
The straightening of the impeller vanes 104 on the impeller 102 from geometry 110 to geometry 112 results in a change in the impeller and diffuser blade angles, which gives a corresponding increase in head and causes a pump curve to level-out. An efficiency curve shifts with every change in impeller exit blade angle and diffuser inlet blade entry angle. Efficiency curve 308 shows the efficiency at, for example, the first impeller geometry 110 and a first diffuser geometry 120, while efficiency curve 310 shows the efficiency at, for example, the second impeller geometry 112 and a second diffuser geometry 122. As the impeller geometry is actuated from a first geometry 110 to a second geometry 112, the efficiency curve will shift as well; the efficiency curve 304 is essentially a composite of all of those possible efficiency curves for the adaptable impeller 102 with vanes 104 that can vary from geometry 110 to geometry 112. As the pump impeller vanes 104 actuate, the diffuser of the same pump stage can actuate as well to maintain a pump efficiency across a wide range of flow-rates.
The adaptive pump impeller can be made using a combination of impeller materials, such as steel, and a shape memory material (SMM), such as a shape memory polymer (SMP) or shape memory alloy (SMA). SMPs are materials in which large deformation can be induced and recovered using external stimuli, trigger, activation, or actuation. Such activation can be from thermal, light, magnetic, or electrical effects.
In implementations in which an SMP is activated by thermal changes, the SMP is first engineered and fabricated to its desired permanent shape. The fabrication can be done with a variety of methods, including molding and curing. The desired temporary shape is processed after the initial fabrication of the item.
In the initial fabrication, the manufactured permanent shape is heated to above the glass transition temperature (Tg) of the SMP. Subsequently, a load is applied to the SMP to deform it to the target temporary shape. With the SMP still loaded or constrained in its temporary shape, it is cooled below its glass transition temperature (Tg), such as near room temperature. After reaching room temperature, the load or constraint is removed and the SMP retains this temporary shape. The adaptive blade of the impeller will have this temporary shape when an adaptive pump stage 100 is assembled. For SMPs engineered and manufactured with a one-way shape memory effect, when the temporary shape is heated to a temperature above the SMP's glass transition temperature, the SMP is transformed to its permanent shape. For SMPs engineered and manufactured with a two-way shape memory effect, when the temporary shape is heated to a temperature above the SMP's glass transition temperature, the SMP is transformed to its permanent shape. However, cooling the SMP below its glass transition temperature causes the SMP to revert back to its temporary shape.
As disclosed earlier, another example of SMM are SMAs, which are metallic alloys with similar characteristics as SMPs and that exhibit one-way and two-way shape memory effects. An SMA with two-way memory can be manufactured such that the engineered permanent shape is shaped into a temporary shape at a high temperature above the SMA's transformation temperature. When cooled, the SMA retains its temporary shape. When heated above its transformation temperature, it changes back to its permanent shape. When cooled below its transition temperature, it reverts back to its temporary shape. The SMA has this temporary shape during pump assembly.
The blades of impellers and diffusers can be encased within a shroud. The upper shroud is in contact with the top portion of a blade, whereas the lower shroud is in contact with the lower portion of a blade.
In some implementations, such as the implementation shown in
The diffuser 412 shown in
Between the movable portion of the impeller blade 428b and either the upper impeller shroud 404 or the lower impeller shroud 406 or both, there can be an impeller elastomeric material 430. The elastomeric material 430 serves as a seal to prevent migration of fluid from one blade cavity to another to help maintain pump efficiency and is attached to both a shroud and the movable portion of the impeller blade 428b. The elastomeric material 430 is flexible enough to maintain its sealing ability as the movable portion of the impeller blade 428b moves from a first geometry 420 to a second geometry 422 (
In downhole oilfield applications, for a pump operating at a given rotational speed and at BEP, when pump flowrate increases, pump head, as well as efficiency decreases, as shown in
There are a number of adaptive materials that can be utilized for an adaptive pump stage. Examples include piezoelectric materials, magnetostrictive materials, shape-memory alloys, shape-memory polymers, pH-sensitive polymers, temperature-responsive polymers, magnetorheological fluid, electroactive polymers, thermoelectric materials, and other adaptive materials. Any of these materials can be used either alone or in any combination to achieve the desired performance of the adaptable pump stage.
Piezoelectric materials produce electrical charge when stress is applied. The effect is also reversible, when a voltage is applied the materials deform. Piezoelectric materials can be used to build adaptive stages to make certain sections bend, expand, or contract when a voltage signal is applied from the charge source and controller. In some implementations, the leading or trailing regions of the blade are made of piezoelectric materials and can be actively adjusted using a voltage signal that is produced by a control piezoelectric surface located in the inlet of the pump. Such a design provides the stage with the ability to auto-adjust the shape of the blade as a function of the flow rate, sand, or other debris in the fluid.
Electroactive polymers exhibit a change in size or shape when stimulated by an electric field. Electroactive polymers can be used in similar application to the one described for piezoelectric materials. An impeller can look like the impeller of
Thermoelectric materials are used to build devices that convert temperature differences into electricity and vice versa. Thermoelectric materials can be used in combination with piezoelectrical materials to achieve changes in performance with changes in fluid temperature. An impeller can look like the impeller of
Magnetostrictive materials change shape when a magnetic field is applied. Another implementation of this disclosure has the leading or trailing regions of the blade made of magnetostrictive materials and can be actively adjusted using external electromagnets located in the housing of the pump. The electromagnets can be powered from the surface of the wellbore using the same ESP cable and can be controlled using the motor voltage or frequency. Control signals can also be transmitted along with electrical power to a control box downhole.
Magnetorheological fluids are fluids that change from a fluid state to a near-solid state when exposed to a magnetic force. Magnetorheological fluids can be used in a similar application to the one described for magnetostrictive materials. Since the magnetorheological fluids are fluid, they can be used in combination with other materials. A controller that provides a magnetic stimulus could be used to control the magnetostrictive material, the magnetorheological fluids, or both. An impeller can look like the impeller of
Shape-memory alloys and shape-memory polymers are materials in which large deformation can be induced and recovered through temperature or stress changes. Another implementation of this disclosure has the leading or trailing regions of the blade made of shape-memory materials and can be actively adjusted using changes in the temperature of the impeller. Changes of temperature of the impeller may be a result of flow rate change, fluid density change, gas slugging, or due to other process-related changes. In such implementations, the change in the memory materials is designed such that changes in temperature change the leading or trailing angles of the blade to achieve optimal lifting and power efficiency for different operating conditions. An impeller can look like the impeller of
Certain polymers are pH-sensitive, for example, change in volume when the pH of the surrounding medium changes. Such adaptive materials can be used to change the pump performance in the presence of certain chemicals, for example, salts, asphaltenes, and paraffins. An impeller can look like the impeller of
Temperature-responsive polymers are materials which undergo changes with temperature. Temperature-responsive polymers can be used in a similar application to the one described for shape memory materials. An impeller can look like the impeller of
A number of implementations have been described. Nevertheless, it will be understood that various modifications may be made without departing from the spirit and scope of the disclosure. For example, a multi-stage pump may contain both adaptable stages and traditional pump stages. Accordingly, other implementations are within the scope of the following claims.
This application claims the benefit under 35 U.S.C. § 119(e) of U.S. Patent Application No. 62/437,249, entitled “CENTRIFUGAL PUMP WITH ADAPTIVE STAGES,” filed Dec. 21, 2017, which is incorporated herein by reference in its entirety.
Number | Date | Country | |
---|---|---|---|
62437249 | Dec 2016 | US |
Number | Date | Country | |
---|---|---|---|
Parent | 15645839 | Jul 2017 | US |
Child | 16737274 | US |