A structure, method, and efficiency calculation method for improving the efficiency of a water turbine using a pressure pump.

Abstract

This invention relates to a structure, method, and efficiency calculation method for improving the efficiency of a water turbine using a pressure pump, belonging to the field of hydraulic engineering technology. The structure mainly consists of a forebay, a pressure pump, a pump house, and a backflow valve. A forebay is constructed on one side of the hydropower station's intake for water storage. A pump house is located in the lower part of the forebay's sidewall, and a pressure pump is installed inside the pump house. A backflow valve is installed at the forebay's inlet to prevent water in the forebay from flowing back into the reservoir. When the reservoir water level is low, the pressure pump draws water from the reservoir into the forebay, raising the forebay's water level. When the reservoir water level is higher than the forebay's water level, the backflow valve automatically opens under the reservoir water pressure, allowing water from the reservoir to automatically flow into the forebay, saving energy. This invention is simple in method and structure, and when the reservoir water level is low, it easily increases the operating head of the water turbine, improving the turbine's operating efficiency, reducing water consumption, and increasing the hydropower station's power generation.

Description

Technical Field

[0001] This invention belongs to the field of water conservancy engineering technology, specifically relating to a structure, method, and efficiency calculation method for improving the efficiency of a water turbine using a pressure pump. Background Technology

[0002] Turbine efficiency is a key factor affecting the economic benefits and sustainable development of hydropower stations. Currently, through optimized design, regular maintenance, and improved operation and management, turbine efficiency can be significantly improved, enhancing the overall power generation capacity and economic benefits of hydropower stations. However, each turbine design has a specific rated head and flow range. Within this range, turbine efficiency is typically high, with some large and medium-sized turbines achieving efficiencies exceeding 95%. If the turbine's operating head deviates significantly from its rated head and flow, its efficiency will drastically decrease, sometimes to as low as 30%. Even with new turbines, at the rated head, when the turbine output is only 50% of its rated power, its efficiency will drop to around 80%; if the head is lower than the rated head, its efficiency will continue to decline. Therefore, both the turbine's operating head and actual output affect its efficiency. Furthermore, with the passage of time, turbines also face aging issues, leading to a continuous decrease in efficiency and severely impacting the power generation capacity of hydropower stations. Currently, the design level of water turbines is already very high, and their efficiency can be guaranteed to be above 90%. Relying solely on optimized turbine design and regular maintenance is unlikely to significantly improve efficiency further. Therefore, new methods and approaches are urgently needed to enhance water turbine efficiency.

[0003] Currently, my country has a large number of hydropower stations with an installed capacity of 400 million kW. However, hydropower generation accounts for only about 15% of the country's energy mix, indicating a significantly low proportion of clean energy. A major reason for this is the low operating efficiency of the turbines, which affects the power generation of hydropower stations. One reason for the low turbine operating efficiency is the low water level in the reservoir, resulting in a small operating head for the turbines. During the middle and late stages of the dry season and during the flood season, the water level in front of the reservoir is relatively low due to flood control requirements, leading to a lower operating head for the turbines. Furthermore, low turbine operating efficiency also leads to greater unit vibration, worsening the operating conditions of the turbines, further reducing their efficiency, and also affecting the safety of the turbine piers. Therefore, improving turbine efficiency and increasing the power generation of hydropower stations is one of the key measures to alleviate my country's energy shortage. Summary of the Invention

[0004] To address the problem that existing hydroelectric turbines experience a significant efficiency drop when the operating head is far below the rated head, this invention proposes a structure, method, and efficiency calculation method for improving turbine efficiency using a pressure pump. A forebay is constructed on the intake side of the hydroelectric power station for water storage. When the reservoir water level is low, water can be drawn from the reservoir using a pressure pump and injected into the forebay, raising the forebay's water level and ensuring it remains high. This increases the turbine's operating head and improves its efficiency. Simultaneously, the turbine operates smoothly during high-efficiency operation, reducing turbine vibration and contributing to the safety of the hydroelectric power station building.

[0005] The technical solution adopted in this invention is: a structure for improving the efficiency of a water turbine by using a pressure pump, including a forebay 1, a pressure pump 2, a pump house 3, a forebay inlet 4, a forebay outlet 5, a hydropower station inlet 7, a water level sensor 8, a backflow valve I 9, a backflow valve II 10, and a control system 11;

[0006] The forebay 1 is built on the upstream side of the hydropower station intake 7, and is enclosed by side walls, bottom slab and dam. The bottom slab elevation of the forebay 1 is lower than that of the bottom slab of the hydropower station intake 7. The pressure pump 2 is installed in the pump house 3 in the middle and lower part of the side wall of the forebay 1. The forebay intake 4 is arranged at the bottom of the side wall of the forebay 1. The backflow valve I 9 and backflow valve II 10 are installed at the end of the forebay intake 4 at the bottom of the pump house 3, with backflow valve I 9 located upstream of the pressure chamber intake of the pressure pump 2 and backflow valve II 10 arranged downstream of the pressure chamber intake of the pressure pump 2. The forebay discharge outlet 5 is arranged at the top of the side wall of the forebay 1. The water level sensor 8 is arranged at the top of the side wall of the forebay 1 and extends into the forebay 1. The pressure pump 2 and the water level sensor 8 are both connected to the control system 11.

[0007] Preferably, a trash rack 6 is arranged at the front end of the forebay inlet 4 on the side closest to the reservoir.

[0008] Preferably, the elevation of the top of the side wall of the forebay 1 is consistent with the elevation of the top of the dam.

[0009] Preferably, the elevation of the bottom slab of the forebay 1 is approximately 1.0m lower than the elevation of the bottom slab of the hydropower station intake 7.

[0010] Preferably, the volume of the forebay 1 is the amount of water that the turbine operates at its rated flow rate for 60-90 seconds.

[0011] Preferably, the maximum water lifting capacity of the pressure pump 2 is matched with the rated flow rate of the water turbine.

[0012] Preferably, the control system 11 is located in the central control room of the hydropower station.

[0013] A method for improving the efficiency of a water turbine using a pressure pump, employing the aforementioned structure for improving water turbine efficiency using a pressure pump, comprises the following specific steps:

[0014] Step 1: The water level sensor 8 senses the water level of the forebay 1 and transmits the detected water level information to the control system 11. The control system 11 calculates the working head of the turbine based on the water level of the forebay 1 and the water level downstream of the hydropower station.

[0015] Step 2: If the water level in the reservoir is higher than the water level in the forebay 1, and the working head of the turbine is higher than the rated head of the turbine, the control system 11 controls the pressure pump 2 to not work. The backflow valve I9 ​​and backflow valve II 10 open directly under the water pressure in the reservoir, and the water in the reservoir flows directly into the forebay 1 through the backflow valve I9 ​​and backflow valve II 10. If the water level in the reservoir is lower than the water level in the forebay 1, and the working head of the turbine is lower than the rated head of the turbine, the backflow valve I9 ​​and backflow valve II 10 close automatically under the action of the backflow. At this time, the control system 11 connects the circuit of the pressure pump 2, and the pressure pump 2 starts to work.

[0016] Step 3: When pressure pump 2 draws water, the pressure chamber of pressure pump 2 generates negative pressure, backflow valve I 9 opens and backflow valve II 10 closes, and water enters the pressure chamber of pressure pump 2 from the forebay inlet 4;

[0017] Step 4: When pressure pump 2 drains water, under the action of water pressure in the pressure chamber, backflow valve I 9 closes and backflow valve II 10 opens, and water is discharged from the pressure chamber of pressure pump 2 into the forebay 1, thus realizing the pumping of water from the reservoir into the forebay 1.

[0018] Step 5: As the water level in the forebay 1 continues to increase, when the control system 11 calculates that the working head of the turbine has reached the rated head, the control system 11 controls the pressure pump 2 to stop working.

[0019] A method for calculating the efficiency improvement of a hydraulic turbine using a pressure pump, comprising the following steps:

[0020] Assuming the areas of the turbine inlet and the pressure pump 2 inlet are both A, then

[0021] The turbine output p1 before the water level is raised is

[0022] (1)

[0023] Where: η1—efficiency of the turbine before water level rise; γ—specific weight of water; μ—inlet flow coefficient; h1—operating head of the turbine before water level rise;

[0024] After the water level is raised, the turbine output p2 is

[0025] (2)

[0026] Where: η2—efficiency of the turbine after water level is raised; h2—working head of the turbine after water level is raised;

[0027] Since pressure pump 2 requires electrical energy to lift water, the power consumption p3 is...

[0028] (3)

[0029] Where: η3—efficiency of the pressure pump; Δh—lift head of the pressure pump;

[0030] The lifting head Δh of pressure pump 2 is

[0031] Δh = h2 - h1 (4)

[0032] Then the actual output of the turbine after the water level is raised is

[0033] (5)

[0034] (6)

[0035] Equation (6) shows that the lifting efficiency of the water turbine is increasing. As h2 / h1 increases, η2 / η1 will also increase, and p2' / p1 will also increase. Therefore, the efficiency of the water turbine will continue to improve.

[0036] The beneficial effects of this invention are:

[0037] (1) When the water level in the reservoir is low, the working head of the turbine is low, resulting in low operating efficiency. By building a reservoir at the intake of the hydropower station, the water level at the intake of the hydropower station can be increased, thereby increasing the working head of the turbine, thus improving the efficiency of the turbine and increasing the power generation of the hydropower station.

[0038] (2) It can reduce the impact of the turbine being in an unfavorable operating condition, so that it can operate in the high-efficiency zone for a long time, thereby improving the reliability and service life of the equipment.

[0039] (3) This method is simple and reliable. Compared with the optimization design of water turbines, it is easier to implement and does not require the replacement of the original water turbine unit, thus improving the utilization rate of the equipment. Attached Figure Description

[0040] Figure 1 This is a typical cross-sectional schematic diagram of the present invention;

[0041] Figure 2 This is a typical planar schematic diagram of the present invention;

[0042] Figure 3 This is a schematic diagram of the upstream position of the present invention;

[0043] Figure 4 This is a schematic diagram of the control system of the present invention.

[0044] The numbers in the diagram are as follows: Forebay-1, Pressure Pump-2, Pump House-3, Forebay Inlet-4, Forebay Outlet-5, Trash Rack-6, Hydropower Station Inlet-7, Water Level Sensor-8, Backflow Valve I-9, Backflow Valve II-10, Control System-11. Detailed Implementation

[0045] The present invention will be further described below with reference to the accompanying drawings and embodiments, but the scope of the present invention is not limited to the description.

[0046] Example 1: A structure for improving the efficiency of a water turbine using a pressure pump, including a forebay 1, a pressure pump 2, a pump house 3, a forebay inlet 4, a forebay outlet 5, a hydropower station inlet 7, a water level sensor 8, a backflow valve I 9, a backflow valve II 10, and a control system 11;

[0047] The forebay 1 is built upstream of the hydropower station intake 7 and is enclosed by side walls, a bottom slab, and a dam. The bottom slab elevation of the forebay 1 is lower than that of the hydropower station intake 7. The pressure pump 2 is installed in the pump house 3 in the lower middle part of the side wall of the forebay 1. The forebay intake 4 is located at the bottom of the side wall of the forebay 1. The backflow valve I 9 and backflow valve II 10 are installed at the end of the forebay intake 4 at the bottom of the pump house 3. Specifically, backflow valve I 9 is located upstream of the pressure chamber intake of the pressure pump 2, and backflow valve II 10 is located downstream of the pressure chamber intake of the pressure pump 2. The forebay drain 5 is located at the top of the side wall of the forebay 1 and is used to drain excess water from the forebay 1. The water level sensor 8 is located at the top of the side wall of the forebay 1 and extends into the forebay about 0.5m using a bracket to measure the water level of the forebay 1 in real time. The pressure pump 2 and the water level sensor 8 are both connected to the control system 11.

[0048] The forebay 1 is built upstream of the hydropower station's intake 7 to store water and increase the turbine's operating head. When the reservoir water level is low, pressure pump 2 pumps water from the reservoir into the forebay 1, raising the water level and thus increasing the turbine's operating head and efficiency. The pressure pump 2 is automatically controlled by control system 11 to ensure the turbine operates within its rated head range. Excess water in the forebay 1 can be discharged into the reservoir through the forebay outlet 5. Backflow valves I9 and II 10 have unidirectional flow function to prevent water in the forebay 1 from flowing back into the reservoir. Additionally, when the forebay 1 needs dredging, backflow valves I9 and II 10 can be manually opened to use a sludge pump for dredging.

[0049] Furthermore, a debris rack 6 is arranged at the front end of the forebay inlet 4 on the side near the reservoir to prevent large floating objects from entering and affecting the operation of the pressure pump 2, backflow valve I 9 and backflow valve II 10.

[0050] Furthermore, the elevation of the top of the side wall of the forebay 1 is consistent with the elevation of the top of the dam.

[0051] Furthermore, the elevation of the bottom slab of the forebay 1 is approximately 1.0m lower than the elevation of the bottom slab of the hydropower station's intake 7.

[0052] Furthermore, the volume of the forebay 1 is the amount of water that the turbine operates at its rated flow rate for 60-90 seconds.

[0053] Furthermore, the maximum water lifting capacity of the pressure pump 2 is matched with the rated flow rate of the water turbine.

[0054] Furthermore, the control system 11 is located in the central control room of the hydropower station.

[0055] A method for improving the efficiency of a water turbine using a pressure pump, employing the aforementioned structure for improving water turbine efficiency using a pressure pump, comprises the following specific steps:

[0056] Step 1: The water level sensor 8 senses the water level of the forebay 1 and transmits the detected water level information to the control system 11. The control system 11 calculates the working head of the turbine based on the water level of the forebay 1 and the water level downstream of the hydropower station.

[0057] Step 2: If the water level in the reservoir is higher than the water level in the forebay 1, and the working head of the turbine is higher than the rated head of the turbine, the control system 11 controls the pressure pump 2 to not work. The backflow valve I 9 and backflow valve II 10 open directly under the water pressure in the reservoir, and the water in the reservoir flows directly into the forebay 1 through the backflow valve I 9 and backflow valve II 10 to supply the power generation needs. If the water level in the reservoir is lower than the water level in the forebay 1, and the working head of the turbine is lower than the rated head of the turbine, the backflow valve I 9 and backflow valve II 10 close automatically under the action of the backflow to prevent the water in the forebay 1 from flowing back into the reservoir. At this time, the control system 11 connects the circuit of the pressure pump 2, and the pressure pump 2 starts to work.

[0058] Step 3: When pressure pump 2 draws water, the pressure chamber of pressure pump 2 generates negative pressure, backflow valve I 9 opens and backflow valve II 10 closes, and water enters the pressure chamber of pressure pump 2 from the forebay inlet 4;

[0059] Step 4: When pressure pump 2 drains water, under the action of water pressure in the pressure chamber, backflow valve I 9 closes and backflow valve II 10 opens, and water is discharged from the pressure chamber of pressure pump 2 into the forebay 1, thus realizing the pumping of water from the reservoir into the forebay 1.

[0060] Step 5: As the water level in the forebay 1 continues to increase, when the control system 11 calculates that the working head of the turbine has reached the rated head, the control system 11 controls the pressure pump 2 to stop working.

[0061] A method for calculating the efficiency improvement of a hydraulic turbine using a pressure pump, comprising the following steps:

[0062] Assuming the areas of the turbine inlet and the pressure pump 2 inlet are both A, then

[0063] The turbine output p1 before the water level is raised is

[0064] (1)

[0065] Where: η1—efficiency of the turbine before water level rise; γ—specific weight of water; μ—inlet flow coefficient; h1—operating head of the turbine before water level rise;

[0066] After the water level is raised, the turbine output p2 is

[0067] (2)

[0068] Where: η2—efficiency of the turbine after water level is raised; h2—working head of the turbine after water level is raised;

[0069] Since pressure pump 2 requires electrical energy to lift water, the power consumption p3 is...

[0070] (3)

[0071] Where: η3—efficiency of the pressure pump; Δh—lift head of the pressure pump;

[0072] The lifting head Δh of pressure pump 2 is

[0073] Δh = h2 - h1 (4)

[0074] Then the actual output of the turbine after the water level is raised is

[0075] (5)

[0076] (6)

[0077] Equation (6) shows that the lifting efficiency of the water turbine increases as h2 / h1 increases, η2 / η1 increases, p2' / p1 increases, and the efficiency of the water turbine increases.

[0078] If we take h2 / h1=2 and η2 / η1=1.28, then p2' / p1=2.15, and the actual output of the turbine will increase by 115%, which is a very significant effect.

[0079] This invention proposes a structure, method, and efficiency calculation method for improving the efficiency of a hydroelectric turbine using a pressure pump. This addresses the problem of low turbine operating efficiency in most existing hydroelectric power stations during the flood season due to low reservoir water levels. When reservoir water levels are low, the invention conveniently increases the turbine's operating head, significantly improving turbine efficiency, reducing water consumption, increasing power generation, and enhancing the economic benefits of the hydroelectric power station. Simultaneously, it contributes to achieving the national "dual carbon" target. Furthermore, the method and structure of this invention are simple and convenient.

[0080] The specific embodiments of the present invention have been described in detail above with reference to the accompanying drawings. However, the present invention is not limited to the above embodiments. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of the present invention.

Claims

1. A structure for improving the efficiency of a water turbine using a pressure pump, characterized in that: Includes forebay (1), pressure pump (2), pump house (3), forebay inlet (4), forebay outlet (5), hydropower station inlet (7), water level sensor (8), backflow valve I (9), backflow valve II (10), and control system (11); The forebay (1) is built on the upstream side of the hydropower station intake (7), and is enclosed by side walls, bottom slab and dam. The bottom slab elevation of the forebay (1) is lower than the bottom slab elevation of the hydropower station intake (7). The pressure pump (2) is installed in the pump house (3) in the lower middle part of the side wall of the forebay (1). The forebay intake (4) is located at the bottom of the side wall of the forebay (1). Backflow valve I (9) and backflow valve II are also located in the forebay (1). (10) is installed at the end of the forebay inlet (4) at the bottom of the pump room (3) and the backflow valve I (9) is located upstream of the pressure chamber inlet of the pressure pump (2). The backflow valve II (10) is arranged downstream of the pressure chamber inlet of the pressure pump (2). The forebay drain (5) is arranged at the top of the side wall of the forebay (1). The water level sensor (8) is arranged at the top of the side wall of the forebay (1) and extends into the forebay (1). The pressure pump (2) and the water level sensor (8) are both connected to the control system (11).

2. The structure for improving turbine efficiency using a pressure pump according to claim 1, characterized in that: A trash rack (6) is arranged at the front end of the forebay inlet (4) on the side near the reservoir.

3. The structure for improving turbine efficiency using a pressure pump according to claim 1, characterized in that: The elevation of the top of the side wall of the forebay (1) is consistent with the elevation of the top of the dam.

4. The structure for improving turbine efficiency using a pressure pump according to claim 1, characterized in that: The bottom elevation of the forebay (1) is about 1.0m lower than the bottom elevation of the hydropower station inlet (7).

5. The structure for improving the efficiency of a water turbine using a pressure pump according to claim 1, characterized in that: The volume of the forebay (1) is the amount of water that the turbine operates at its rated flow rate for 60-90 seconds.

6. The structure for improving the efficiency of a water turbine using a pressure pump according to claim 1, characterized in that: The maximum water lifting capacity of the pressure pump (2) is matched with the rated flow rate of the turbine.

7. The structure for improving the efficiency of a water turbine using a pressure pump according to claim 1, characterized in that: The control system (11) is located in the central control room of the hydropower station.

8. A method for improving the efficiency of a water turbine using a pressure pump, characterized in that: The specific steps of using the structure described in any one of claims 1-7, which utilizes a pressure pump to improve the efficiency of a water turbine, are as follows: Step 1: The water level sensor (8) senses the water level of the forebay (1) and transmits the detected water level information to the control system (11). The control system (11) calculates the working head of the turbine based on the water level of the forebay (1) and the water level downstream of the hydropower station. Step 2: If the water level in the reservoir is higher than the water level in the forebay (1), and the working head of the turbine is higher than the rated head of the turbine, the control system (11) controls the pressure pump (2) to not work, and the backflow valve I (9) and backflow valve II (10) open directly under the water pressure in the reservoir, and the water in the reservoir flows directly into the forebay (1) through the backflow valve I (9) and backflow valve II (10); if the water level in the reservoir is lower than the water level in the forebay (1), and the working head of the turbine is lower than the rated head of the turbine, the backflow valve I (9) and backflow valve II (10) close automatically under the action of the backflow, and at this time the control system (11) connects the circuit of the pressure pump (2), and the pressure pump (2) starts to work; Step 3: When the pressure pump (2) draws water, the pressure chamber of the pressure pump (2) generates negative pressure, the backflow valve I (9) opens and the backflow valve II (10) closes, and water enters the pressure chamber of the pressure pump (2) from the forebay inlet (4); Step 4: When the pressure pump (2) drains water, the backflow valve I (9) closes and the backflow valve II (10) opens under the action of water pressure in the pressure chamber. Water is discharged from the pressure chamber of the pressure pump (2) into the forepool (1), thus realizing the pumping of water from the reservoir into the forepool (1). Step 5: As the water level in the forebay (1) continues to increase, when the control system (11) calculates that the working head of the turbine has reached the rated head, the control system (11) controls the pressure pump (2) to stop working.

9. A method for calculating the efficiency improvement of a water turbine using a pressure pump, characterized in that: The method for improving turbine efficiency using a pressure pump as described in claim 8 includes the following steps: Assuming the areas of the turbine inlet and the pressure pump (2) inlet are both A, then The turbine output p1 before the water level is raised is （1） Where: η1—efficiency of the turbine before water level rise; γ—specific weight of water; μ—inlet flow coefficient; h1—operating head of the turbine before water level rise; After the water level is raised, the turbine output p2 is （2） Where: η2—efficiency of the turbine after water level is raised; h2—working head of the turbine after water level is raised; Since the pressure pump (2) needs to consume electrical energy to lift water, the power consumption p3 is... （3） Where: η3—efficiency of the pressure pump; Δh—lift head of the pressure pump; The lifting head Δh of the pressure pump (2) is Δh = h2 - h1 (4) Then the actual output of the turbine after the water level is raised is （5） （6） Equation (6) shows that the lifting efficiency of the water turbine is increasing. As h2 / h1 increases, η2 / η1 will also increase, and p2' / p1 will also increase. Therefore, the efficiency of the water turbine will continue to improve.

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