Patent Application
20130097994
The present invention relates to turbine engines and, more particularly, to a turbine engine using multiple working fluids.
A gas turbine is a heat engine that performs mechanical work using gas at its working fluid. In a gas turbine, gases passing through the gas turbine undergo three thermodynamic processes. These are isentropic compression, isobaric (constant pressure) combustion and isentropic expansion. Together these make up the Brayton cycle. As with all cyclic heat engines, higher combustion temperatures can generally allow for greater efficiencies. However, temperatures are limited by the ability of the steel, nickel, ceramic, or other materials that make up the engine to withstand high temperatures and stresses.
A steam engine is a heat engine that performs mechanical work using steam as its working fluid. In a steam engine, water turns to steam and reaches a high pressure. When expanded through a turbine, mechanical work is done. The reduced-pressure steam is then released into the atmosphere or recycled. The thermodynamic cycle used to analyze this process is called the Rankine cycle.
A combined-cycle engine combines the Brayton cycle and the Rankine cycle. One such combined-cycled engine is disclosed in U.S. Pat. No. 4,248,039 to Dah Yu Cheng.
In one independent embodiment, a multi-fluid turbine engine may generally include a turbine, a first working fluid inlet passage, and a second working fluid inlet passage. The turbine may include a first working fluid portion and a second working fluid portion. The first working fluid passage may be configured to introduce a first working fluid to the first working fluid portion to perform work on the first working fluid portion, and the second working fluid inlet passage may be configured to introduce a second working fluid to the second working fluid portion to perform work on the second working fluid portion. The first working fluid inlet passage and the second working fluid passage may be independent of each other.
In another independent embodiment, a multi-fluid turbine engine may generally include a turbine for converting energy of working fluids into mechanical energy. The turbine may be divided into a number of working fluid portions for respectively receiving different working fluids. The working fluid portions may be divided by a plane through the turbine such that a turbine part included in each of the working fluid portions is always changing as the turbine rotates.
In still another independent embodiment, a multi-fluid turbine engine may generally include a turbine, a gas inlet passage, a steam inlet passage, a gas outlet passage, and a steam outlet passage. The turbine may be divided into a gas portion and a steam portion. The gas inlet passage may be configured to introduce gas to the gas portion of the turbine to perform work on the gas portion. The steam inlet passage may be configured to introduce steam to the steam portion of the turbine to perform work on the steam portion. The gas inlet passage and the steam inlet passage may be independent of each other. The gas outlet passage may be configured to receive gas exhausted from the gas portion of the turbine. The steam outlet passage may be configured to receive steam exhausted from the steam portion of the turbine.
Other independent aspects of the invention will become apparent by consideration of the detailed description, claims and accompanying drawings.
Before any independent embodiments of the invention are explained in detail, it is to be understood that the invention is not limited in its application to the details of construction and the arrangement of components set forth in the following description or illustrated in the following drawings. The invention is capable of other independent embodiments and of being practiced or of being carried out in various ways. Also, it is to be understood that the phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting. Use of “including” and “comprising” and variations thereof as used herein is meant to encompass the items listed thereafter and equivalents thereof as well as additional items. Use of “consisting of” and variations thereof as used herein is meant to encompass only the items listed thereafter and equivalents thereof. Further, it is to be understood that such terms as “forward”, “rearward”, “left”, “right”, “upward” and “downward”, etc., are words of convenience and are not to be construed as limiting terms.
To illustrate the concept that the first working fluid and the second fluid are respectively introduced to different turbine portions to perform work, the turbine 20 is described as being divided into the first turbine portion 20A and the second turbine portion 20B. From this viewpoint, the first and second turbine portions may also be termed as first and second working fluid portions, respectively. It is noted, however, that the first turbine portion 20A and the second turbine portion 20B described therein are not specific fixed parts on the turbine 20. Rather, the first turbine portion 20A and the second turbine portion 20B refer to first and second parts of the turbine 20 that are divided by the boundary line C1-O-C2 at any given time point. For example, in
While the turbine 20 is described as being divided into the first working fluid portion 20 and the second working fluid portion 20B by the boundary line C1-O-C2, it is noted that this does not require the turbine 20 itself be designed and manufactured to have such a boundary line C1-O-C2. Rather, this boundary line C1-O-C2 is defined by working fluid inlet passages which are discussed below.
In one embodiment, the first working fluid may include gas, and the second working fluid may include water or steam (steam can be considered as vapor water so sometimes the steam is also termed as water). Accordingly, the first and second turbine portions are sometimes also termed as gas and steam portions. The gas and steam (or water) are two types of most common working fluids used in current turbine engines.
The gas refers to a combustion product of a fuel. The fuel may include, but is not limited to, for example, gasoline, natural gas, propane, diesel oil, kerosene, a renewable fuel, such as E85 alcohol-gasoline, biodiesel and biogas, etc. In other independent embodiments, the first working fluid and the second working fluid may also be other working fluids other than those described above.
When the first working fluid includes the combustion product and the second working fluid includes the steam, the multi-fluid turbine engine described above combines the work performed in the Brayton cycle and the work performed in the Rankine cycle on the same turbine. In comparison with the existing gas-steam combined cycle, the multi-fluid turbine engine described above can have a more compact structure.
As mentioned above, in general, higher turbine inlet temperature results in a higher capability of the gas to perform work and hence a higher efficiency of the turbine engine. However, as the turbine inlet temperature becomes higher and higher, components of turbine, such as the blades, are required to have an increasingly higher heat-resistant capability. The temperature of the working fluid for the Brayton cycle usually exceeds 1000° C. and some even exceed 2000° C. In contrast, the temperature of the working fluid for the Rankine cycle is much lower, usually less than 700° C.
In the illustrated multi-fluid turbine engine, the gas and steam perform work on their respective turbine portions 20A, 20B. As such, at any given time point, only part of the turbine 20 receives the high temperature gas, while the remaining part of the turbine receives the relatively lower temperature steam. As the turbine 20 continuously rotates, the turbine part in the gas portion that receives the high temperature gas can continuously rotate to the steam portion to receive the steam to be cooled by the relatively lower temperature steam.
Also, because the gas and the steam perform work on their respective turbine portions, the steam does not cause a reduction of the temperature of the gas (turbine inlet temperature). In other words, the introduction of the steam does not reduce the capability of the gas to perform work.
The turbine 20 is divided by a horizontal boundary line C1-O-C2 (with O being the center of the turbine) into a first working fluid portion 20A and a second working fluid portion 20B, each occupying one half of the turbine 20 in the illustrated embodiment. As such, the first working fluid (for example, gas) is introduced to the turbine 20 at one side of the boundary line C1-O-C2, for example, the first working fluid portion 20A above the boundary line C1-O-C2, while the second working fluid (for example, steam) is introduced to the turbine 20 at the other side of the boundary line, for example, the second working fluid portion 20B below the boundary line C1-O-C2. In other words, the first working fluid and the second working fluid have a horizontal inlet boundary line C1-O-C2 at the inlet side 22 of the turbine 20.
Because the turbine 20 continuously rotates in the clockwise direction, the working fluids are also driven to rotate along the clockwise direction R with the turbine 20 when passing through the turbine 20. As a result, when the working fluids leave the turbine 20, the working fluids as a whole deflect along the rotational direction of the turbine at a deflection angle α with respect to the state just before reaching the turbine 20. That is, the first working fluid and the second working fluid leaving the turbine 20 have an outlet boundary line C1′-O-C2′ at the outlet side 24 of the turbine 20, and the outlet boundary line C1′-O-C2′ deflects along the rotational direction at the deflection angle α with respect to the inlet boundary line C1-O-C2. If it is desired to separately process the first working fluid and the second working fluid leaving the turbine 20, this deflection angle must be taken into account. It is to be understood that
The deflection angle α is dependent on parameters such as, for example, turbine inlet pressure and temperature, inlet/exhaust passage parameters, turbine rotational speed, exhaust back pressure, or the like. For example, the deflection angle α decreases with the increase of turbine inlet pressure and temperature, the decrease of the turbine rotational speed, and the decrease of the exhaust back pressure.
A first working fluid inlet pipe 126 and a second working fluid inlet pipe 128 are disposed at the inlet side of the turbine 120. The first working fluid inlet pipe 126 is in fluid communication with the first working fluid guide portion 122A of the turbine stator 122, such that the first working fluid is introduced to the first working fluid guide portion 122A of the stator 122 and then guided through the first working fluid guide portion 122A to the first working fluid portion 124A of the turbine rotator 124 for performing work. Therefore, the first working fluid inlet pipe 126 and the first working fluid guide portion 122A of the turbine stator 122 (specifically, spaces formed between blades of the first guide portion 122A) cooperatively form a first working fluid inlet passage through which the first working fluid is introduced to the first working fluid portion 124A of the turbine rotor to perform work.
Similarly, the second working fluid inlet pipe 128 is in fluid communication with the second working fluid guide portion 122B, such that the second working fluid is introduced to the second working fluid guide portion 122B and then guided through the second working fluid guide portion 122B to the second working fluid portion 124B of the turbine rotator 124 for performing work. Therefore, the second working fluid inlet pipe 128 and the second working fluid guide portion 122B of the turbine stator 122 (specifically, spaces formed between blades of the second guide portion 122B) cooperatively form a second working fluid inlet passage through which the second working fluid is introduced to the second working fluid portion 124B of the turbine rotor 124 to perform work. The first working fluid inlet passage and the second working fluid inlet passage are independent of each other to separately transmit the first and second working fluids, respectively.
The first and second working fluids leave the first and second working fluid portions 124A, 124B after performing work on the turbine rotor 124. If it is desired to separately process the first and second working fluids leaving the turbine rotor 124, the turbine engine may include, at the outlet of the turbine 120, a first working fluid outlet pipe or passage 130 and a second working fluid outlet pipe or passage 132 that are independent of each other. The first working fluid outlet passage 130 is in fluid communication with the first working fluid portion 124A to receive substantially only the first working fluid that perform work on the first working fluid portion 124A. The second fluid outlet passage 132 is in fluid communication with the second working fluid portion 124B to receive substantially only the second working fluid that perform work on the second working fluid portion 124B.
As described above, when leaving the turbine 20, the working fluids as a whole deflect at a deflection angle α along the rotational direction of the turbine 20 with respect to a state of the working fluids before reaching the turbine. That is, an outlet boundary line D1′-O-D2′ (see
Accordingly, the first working fluid outlet passage 130 and the second working fluid outlet passage 132 are constructed and disposed such that a fluid receiving boundary line defined between the first working fluid outlet passage 130 and the second working fluid outlet passage 132 deflects at the same deflection angle α in the rotational direction of the turbine rotor 124 with respect to the inlet boundary line D1-O-D2, thereby allowing substantially all of the first working fluid performing on the first working fluid portion 124A to enter the first working fluid outlet passage 130 and substantially all of the second working fluid performing on the second working fluid portion 124B to enter the second working fluid outlet passage 132. The deflection angle α may be determined based on parameters such as, for example, turbine inlet pressure and temperature, inlet/exhaust passage parameters, turbine rotational speed, exhaust back pressure, or the like.
The radial turbine engine includes a turbine 220 with a turbine stator 222 and a turbine rotor 224. The turbine stator 222 includes a first working fluid guide portion 222A and a second working fluid guide portion 222B. The turbine rotor 224 includes a first working fluid portion 224A and a second working fluid portion 224B divided by (see
The turbine engine includes a first working fluid inlet pipe 226 and a second working fluid inlet pipe 228 that are disposed at an inlet side (i.e., a circumferential periphery) of the turbine 120. The first working fluid inlet pipe 226 is in fluid communication with the first working fluid guide portion 222A of the turbine stator 222, such that the first working fluid is introduced to the first working fluid guide portion 222A of the stator 222 and then guided through the first working fluid guide portion 222A to the first working fluid portion 224A of the turbine rotator 224 for performing work. Therefore, the first working fluid inlet pipe 226 and the first working fluid guide portion 222A of the turbine stator 222 (specifically, spaces formed between blades of the first working fluid guide portion 222A) cooperatively form a first working fluid inlet passage through which the first working fluid is introduced to the first working fluid portion 224A to perform work.
Similarly, the second working fluid inlet pipe 228 is in fluid communication with the second working fluid guide portion 222B of the turbine stator 222, such that the second working fluid is introduced to the second working fluid guide portion 222B of the stator 222 and then guided through the second working fluid guide portion 222B to the second working fluid portion 224B of the turbine rotator 224 for performing work. Therefore, the second working fluid inlet pipe 228 and the second working fluid guide portion 222B of the turbine stator 222 (specifically, spaces formed between blades of the second working fluid guide portion 222B) cooperatively form a second working fluid inlet passage through which the second working fluid is introduced to the second working fluid portion 224B to perform work. The first working fluid inlet passage and the second working fluid inlet passage are independent of each other to separately transmit the first and second working fluids, respectively.
The first and second working fluids leave the first and second working fluid portions 224A, 224B after performing work on the turbine rotor 224. If it is desired to separately process the first and second working fluids leaving the turbine rotor 224, the turbine engine may include, at an outlet side of the turbine 220, a first working fluid outlet pipe or passage 230 and a second working fluid outlet pipe or passage 232 that are independent of each other. The first working fluid outlet passage 230 is in fluid communication with the first working fluid portion 224A of the turbine rotor 224 to receive substantially only the first working fluid that performs work on the first working fluid portion 224A. The second working fluid outlet passage 232 is in fluid communication with the second working fluid portion 224B of the turbine rotor 224 to receive substantially only the second working fluid that performs work on the second working fluid portion 224B.
As described above, when leaving the turbine 220, the working fluids as a whole deflect at a deflection angle in the rotational direction of the turbine 220 with respect to a state of the working fluids just before reaching the turbine 220. That is, an outlet boundary line E1′-O-E2′ between the first working fluid and the second working fluid deflects at the deflection angle in the rotational direction of the turbine rotor 224 with respect to the inlet boundary line E1-O-E2.
Accordingly, the first working fluid outlet passage 230 and the second working fluid outlet passage 232 are constructed and disposed such that a fluid receiving boundary line defined between the first working fluid outlet passage 230 and the second working fluid outlet passage 232 deflects at the same deflection angle in the rotational direction of the turbine rotor 224 with respect to the inlet boundary line E1-O-E2, thereby allowing substantially all of the first working fluid performing on the first turbine portion 224A to enter the first working fluid outlet passage 230 and substantially all of the second working fluid performing on the second turbine portion 224B to enter the second working fluid outlet passage 232. The deflection angle may be determined based on parameters such as, for example, turbine inlet pressure and temperature, inlet/exhaust passage parameters, turbine rotational speed, exhaust back pressure, or the like.
While the turbines 20, 220 are illustrated in the above description as a single-stage turbine, it is noted that the concept of different working fluids performing work on different turbine portions can also be implemented in a multi-stage turbine. Because most current multi-stage turbines are multi-stage axial turbines, the following description takes the multi-stage axial turbine as an example. However, it is to be understood that the concept disclosed herein can also be applied to a multi-stage radial turbine.
To simplify the description, in
The first working fluid portion 3202A and the second working fluid portion 3202B of the first stage turbine 3202 are separated by the boundary line F1-O-F2, which means that the first stage inlet boundary line between the first and second working fluids is also the line F1-O-F2. As described above, when the first and second working fluids leave the first and second turbine portions 3202A and 3202B after performing work thereon, the first and second working fluids as a whole deflect at a deflection angle α1 in the rotational direction of the turbine 3202 with respect to the inlet boundary line F1-O-F2. That is, a first stage outlet boundary line F1′-O-F2′ (shown in dashed line) between the first and second working fluids leaving the turbine has the deflection angle α1 with respect to the first stage inlet boundary line F1-O-F2.
When the first and second working fluids leaving the first stage turbine 3202 reach the second stage turbine 3204, the second stage inlet boundary line G1-O-G2 is approximately parallel to the first stage inlet boundary line F1′-O-F2′ and therefore has approximately the same deflection angle α1 with respect to the first stage inlet boundary line F1-O-F2. When the first and second working fluid leave the second stage turbine 3204 after performing work thereon, a second stage outlet boundary line G1′-O-G2′ (shown in dashed line) between the first and second working fluids leaving the second stage turbine 3204 has a deflection angle α2 with respect to the second stage inlet boundary line G1-O-G2. Therefore, with respect to the first stage inlet boundary line F1-O-F2, the second stage outlet boundary line G1′-O-G2′ has approximately a deflection angle α1+α2. As such, after passing through the whole multi-stage turbine, the deflection angle of the first and second working fluids as a whole can be considered as approximately a sum of the deflection angles occurring at respective stage turbines (e.g., α1+α2). If it is desired to separately process (e.g., recycle) the first and second working fluids exhausted from the multi-stage turbine 320, this deflection angle (α1+α2) is taken into account.
In one independent embodiment, the first stage turbine may be a turbine for directly receiving the steam and gas from a steam source and gas source (i.e., combustion chamber), which transmits at least part of its kinetic energy to a compressor of the turbine engine through a transmission shaft. The second stage turbine and the first stage turbine may have no mechanical connection therebetween. The working fluids leaving the first stage turbine continue to perform work on and thus rotate the second stage turbine such that the second stage turbine can drive a load such as a generator.
In those embodiments described above, the turbine is equally divided into two halves in a rotational direction of the turbine. It is to be understood that this particular dividing manner is illustrative rather than restrictive. The turbine may be divided into working fluid portions in the rotational direction of the turbine in a different manner according to parameters and characteristics of the working fluids. For example,
The gas and steam are respectively introduced to different portions of the turbine 420 to perform work. The turbine 420 as well as the inlet and outlet passages 430, 432, 434, 436 may be constructed in the similar manner to those described above with reference to
In the illustrated embodiment, the gas as the first working fluid is supplied from a combustion chamber 440. The combustion chamber 440 may receive compressed air from a compressor 442 and fuel from a fuel source (not shown). Combustion of the fuel and air in the combustion chamber 440 results in the combustion product (i.e., the gas) as the first working fluid.
The steam, as the second working fluid exhausted from the turbine 420, may be recycled by a water recycling system 444. The water recycling system 444 processes and recycles or returns some or all of the steam from the steam outlet passage 436 to the steam inlet passage 432. In the illustrated embodiment, the water recycling system 444 includes a condenser 446 and a recuperator unit.
The condenser 444 is configured to condense the steam from the steam outlet passage 436 into liquid water. The condenser 444 may operate in various manners including, but not limited to, natural cooling, air cooling, water (e.g. sea water) cooling, as long as it can convert the steam into liquid water.
The recuperator unit is configured to heat the liquid water (the second working fluid) condensed by the condenser 446 with the heat recovered from at least one of the gas from the gas outlet passage 434 and the steam from the steam outlet passage 436. In the illustrated embodiment, the recuperator unit includes a first exchanger 448 and a second exchanger 450.
The first heat exchanger 448 heats the condensed liquid water with the heat recovered from the steam from the steam outlet passage 436, such that the liquid water increases in temperature or is heated to steam. The second heat exchanger 450 is connected between the first heat exchanger 448 and the steam inlet passage 432, which further heats the heated water or steam (second working fluid) from the first heat exchanger with the heat recovered from the hot gas from the gas outlet passage 434. The heated steam (second working fluid) then enters the turbine 420 through the steam inlet passage 432.
After heating the steam as the second working fluid, the gas generally still has a high temperature. Therefore, the heat of gas exhausted from the second heat exchanger 450 may be recovered once again, for example, by another heat exchanger (not shown) to heat another fluid.
If the gas and steam were mixed, the condenser may need to be made with a prohibitively large size due to the huge amount of the whole exhaust that needs to be processed. In addition, the gas contains acidic materials that corrode pipes of the water recycling system, which may also increase difficulties in recycling the water if the gas and steam were mixed.
In contrast, in the multi-fluid turbine engine system illustrated in
In one independent embodiment, the water is stored in the water recycling system 444 when the engine is not in operation. Therefore, at the system start-up, there is no steam introduced into the turbine. Rather, only the gas is used during the start-up period. After the system is started, the water stored in the water recycling system 444 is heated by the exhaust gas (first working fluid) to steam (second working fluid) that is then introduced to the turbine to perform work through the steam inlet passage 432.
The gas and steam are respectively introduced to different portions of the turbine 520 to perform work. The turbine 520 as well as the inlet and outlet passages 530, 532, 534, 536 may be constructed in the similar manner to those described above with reference to
As shown in
While the turbine engines of the independent embodiments described above are illustrated as having two different working fluids (i.e., gas and steam), it is to be understood, however, that the concept of different working fluids working on different portions of the turbine is also applicable in situations in which more than two working fluids are used. If more than two working fluids are used, the turbine would include a corresponding number of the working fluid portions, divided accordingly, as well as a corresponding number of the fluid inlet and outlet passages.
In addition, in the context of the present disclosure, the same type of working fluid having a different working parameter (e.g., temperature) can also be considered as a different working fluid. Taking the gas an example, a first gas and a second gas having different temperatures can be considered as two different working fluids although they are both gas. Accordingly, gases (or steam or another working fluid) having different temperatures (or other working parameters) working on different portions of the turbine also falls within the scope of the present invention.
As illustrated in
For example, with respect to working fluids having different temperature, the higher temperature working fluid works on only part of the turbine at any given time point. Therefore, as the turbine continuously rotates, the lower temperature working fluid can cool the turbine part that previously received the higher temperature working fluid, thereby increasing the reliability of the turbine components and prolonging the lifespan of the turbine.
Also, in some independent embodiments, because different working fluids work on different turbine portions, separate processing or recycling of the different exhaust working fluids is made possible. In particular, when water or steam is used as one of the working fluids, this may simplify the process of water recycling and, thus, may reduce the recycling cost.
It will be apparent to those skilled in the art that various modifications and variations can be made to the disclosed structure without departing from the scope or spirit of the invention. In view of the foregoing, it is intended that the present invention cover modifications and variations of this invention provided they fall within the scope of the following claims and their equivalents.
| Number | Date | Country | Kind |
|---|---|---|---|
| 201110318160.7 | Oct 2011 | CN | national |
