Throttling device for combustion chamber pressure regulation and throttling test method

Abstract

The present invention belongs to the field of engine combustion chamber and burner testing, and discloses a throttling device for combustion chamber pressure regulation and a throttling test method. The throttling device realizes stepless regulation of the combustion chamber pressure without an actuating structure by supplying air with a variable flow rate; cold air is used to form an air film to block a part of the high-temperature combustion gas, and combined with water cooling, long-term protection under high-temperature combustion gas working medium is realized together. The throttling device has no actuator, is easy to manufacture, reliable in testing, and can adapt to long-term operation of high-temperature combustion gas. The throttling test method includes installing the throttling device; connecting the air source and the regulating valve; calculating the air flow corresponding to the expected combustion chamber pressure; starting the combustion chamber; supplying air and adjusting the air flow according to the combustion chamber pressure. The throttling test method adjusts the combustion chamber pressure by supplying air, and realizes stepless regulation of the combustion chamber working pressure without an actuating mechanism by controlling the air flow to accurately match the change requirements of the combustion chamber working pressure.

Description

Technical Field

[0001] The invention belongs to the field of engine combustion chamber and burner testing, and in particular relates to a throttling device for regulating combustion chamber pressure and a throttling test method. Background Art

[0002] In the development of new combustion chambers or burners, it is often necessary to conduct performance tests on ignition, combustion, and flame stabilization under different working conditions. Under different working conditions, the combustion chamber corresponds to different working chamber pressures. In order to control the combustion chamber pressure, a fixed throat or other throttling device is often used downstream of the combustion chamber. Since the combustion flow and pressure often do not change proportionally, different combustion chamber downstream throttling elements are required under different working conditions. At present, different downstream throats are usually replaced under different working conditions or a regulating valve control method is used. However, there are the following shortcomings:

[0003] (1) If different downstream throats are used for different operating conditions, multiple throttling devices need to be manufactured, which results in high test costs and low test efficiency, and it is impossible to achieve stepless regulation of the combustion chamber pressure.

[0004] (2) If an actuated regulating valve is used, the design and manufacture of the valve body and regulating device will face great difficulties as the gas temperature usually exceeds 1300°C. From the perspective of practical application, high-temperature thermal protection, high-temperature sealing and regulating accuracy are particularly difficult to resolve.

[0005] Currently, there is an urgent need to develop a throttling device and a throttling test method for regulating the combustion chamber pressure. Summary of the invention

[0006] One technical problem to be solved by the present invention is to provide a throttling device for regulating the combustion chamber pressure. Another technical problem to be solved by the present invention is to provide a throttling test method for regulating the combustion chamber pressure.

[0007] The throttling device for regulating the combustion chamber pressure of the present invention comprises a contraction section, a throat section and an expansion section connected sequentially from front to back;

[0008] A plurality of water cooling channels are arranged in the wall surfaces of the contraction section, the throat section and the expansion section, which are sequentially distributed along the central axis, the water cooling channels are close to the inner wall surface, and each water cooling channel is connected to the water inlet; an annular air replenishing cavity is also arranged, the air replenishing cavity is close to the outer wall surface, and the air replenishing cavity is connected to the air inlet;

[0009] Several groups of air intake channels are arranged in the wall of the contraction section and the throat section and are distributed sequentially along the central axis. The air intake channels are staggered with the water cooling channels. Each group of air intake channels includes several wall air intake holes evenly distributed along the circumference, and each wall air intake hole is connected to the air replenishment cavity.

[0010] Furthermore, the throttling device is used for two types of tests, one is to provide different combustion chamber pressures in different vehicle tests; the other is to dynamically change the combustion chamber pressure in a single test.

[0011] Furthermore, the throttling device is manufactured using a 3D additive printing method.

[0012] Furthermore, a front flange is arranged at the front end of the throttling device, and a rear flange is arranged at the rear end.

[0013] Furthermore, the diameter of the wall air inlet holes ranges from 1 mm to 4 mm, and the ratio of the hole spacing to the hole diameter is (1-3):1.

[0014] Furthermore, the ratio of the intake area of ​​the contraction section to the intake area of ​​the throat section is (2-4):1.

[0015] The throttling test method for combustion chamber pressure regulation of the present invention comprises the following steps:

[0016] S10. Install throttling device;

[0017] The throttling device is connected to the combustion chamber through the front flange and the rear flange arranged at the front and rear; the combustion chamber is an engine combustion chamber or a burner combustion chamber;

[0018] S20. Connect the air source and the regulating valve;

[0019] The air inlet of the throttling device is connected to the air source through the air flow pipeline, and a stop valve and a regulating valve are arranged on the air flow pipeline; the pressure of the air source is more than 2 times the maximum pressure of the combustion chamber during the test, and the air mass of the air source is more than 3 times the total mass of air consumed during the test time;

[0020] S30. Calculate the air flow corresponding to the expected combustion chamber pressure;

[0021] Calculate the air flow rate corresponding to the expected combustion chamber pressure in the test , find the throttling characteristic curve of the regulating valve, determine the expected opening corresponding to the regulating valve, and open the regulating valve to the expected opening;

[0022] S40. Start the combustion chamber;

[0023] Start the combustion chamber, and the combustion chamber enters the working state. Measure the actual combustion chamber pressure. If the actual combustion chamber pressure variation range does not exceed ±6% of the expected combustion chamber pressure, start the throttling device test.

[0024] S50 supply air and adjust the air flow according to the combustion chamber pressure;

[0025] Adjust the opening of the air control valve to change the air flow rate, compare and feedback control the actual combustion chamber pressure with the expected combustion chamber pressure; continue to adjust the opening of the air control valve to control the deviation between the actual combustion chamber pressure and the expected combustion chamber pressure within ±2%, and record the adjustment time of the air control valve. If the adjustment time is less than or equal to 0.5s, the throttling device achieves the expected effect.

[0026] Furthermore, the air flow The calculation process is as follows:

[0027] S31. Assume that the flow area of ​​the throat section of the throttling device is A t , the gas flow rate is , gas temperature is , the air temperature is , , then according to the energy conservation principle before and after the gas and air are mixed, the average temperature of the mixed gas after mixing is obtained T m :

[0028] ;

[0029] In the formula, , and Represent gas, air and mixed gas respectively. , and They represent the specific enthalpy of gas, air and mixed gas at the corresponding temperature. When the temperature and gas composition are known, they can be obtained by looking up the Jnaff table. , and The value of the mixed gas after mixing is obtained T m ;

[0030] S32. Calculate the air flow rate using the one-dimensional air flow blockage formula :

[0031] ;

[0032] In the formula, is the expected combustion chamber pressure, is the gas specific heat ratio, is the gas constant.

[0033] The throttling device for combustion chamber pressure regulation and the throttling test method of the present invention have the following characteristics:

[0034] 1. The throttling device realizes stepless regulation of the combustion chamber pressure without an actuating structure by supplying variable flow of air;

[0035] 2. The throttling device uses cold air to form an air film to block a part of the high-temperature gas, and then combines it with water cooling to achieve long-term protection under high-temperature gas working medium;

[0036] 3. The throttling control method supplies cooling water and air to the throttling device at the same time, calculates and sets the air regulating valve opening according to the working pressure requirements of the combustion chamber, and then fine-tunes the air regulating valve opening through pressure feedback, thereby achieving high-precision regulation of the combustion chamber pressure.

[0037] The throttling test method for combustion chamber pressure regulation of the present invention can meet two types of typical tests by calculating the opening of the air regulating valve and combining the pressure feedback PID control of the air regulating valve: one is to provide different combustion chamber pressures in different vehicle tests; the other is to dynamically change the combustion chamber pressure in a single test.

[0038] In short, the throttling device for regulating the combustion chamber pressure of the present invention has no actuator, is easy to manufacture, reliable in testing, and can adapt to long-term operation of high-temperature fuel gas; the throttling test method for regulating the combustion chamber pressure of the present invention regulates the combustion chamber pressure by supplying air, and controls the air flow to accurately match the change requirements of the combustion chamber working pressure, thereby realizing stepless regulation of the combustion chamber working pressure without an actuator. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 The throttling device for regulating the combustion chamber pressure of the present invention (cross-sectional view);

[0040] Figure 2 The throttling device for regulating the combustion chamber pressure of the present invention (stereoscopic view).

[0041] In the figure, 1. wall air inlet; 2. contraction section; 3. throat section; 4. water cooling channel; 5. air supply cavity; 6. expansion section; 7. front flange; 8. rear flange; 9. air inlet; 10. water inlet. DETAILED DESCRIPTION

[0042] The present invention will be described below in conjunction with the accompanying drawings and embodiments.

[0043] Example: Figure 1 , Figure 2 As shown, the throttling device for regulating the combustion chamber pressure in this embodiment includes a contraction section 2, a throat section 3 and an expansion section 6 connected sequentially from front to back;

[0044] A plurality of water cooling channels 4 are arranged in the wall surface of the contraction section 2, the throat section 3 and the expansion section 6, which are sequentially distributed along the central axis. The water cooling channels 4 are close to the inner wall surface, and each water cooling channel 4 is connected to the water inlet 10. An annular air replenishing cavity 5 is also arranged, and the air replenishing cavity 5 is close to the outer wall surface, and the air replenishing cavity 5 is connected to the air inlet 9.

[0045] A plurality of groups of air inlet channels are arranged in the wall of the contraction section 2 and the throat section 3 and are sequentially distributed along the central axis. The air inlet channels are staggered with the water cooling channels 4. Each group of air inlet channels includes a plurality of wall air inlet holes 1 uniformly distributed along the circumferential direction. Each wall air inlet hole 1 is connected to the air replenishment cavity 5.

[0046] Furthermore, the throttling device is used for two types of tests, one is to provide different combustion chamber pressures in different vehicle tests; the other is to dynamically change the combustion chamber pressure in a single test.

[0047] Furthermore, the throttling device is manufactured using a 3D additive printing method.

[0048] Furthermore, a front flange 7 is provided at the front end of the throttling device, and a rear flange 8 is provided at the rear end.

[0049] Furthermore, the diameter of the wall air inlet holes 1 ranges from 1 mm to 4 mm, and the ratio of the hole spacing to the hole diameter is 1 to 3:1.

[0050] Furthermore, the ratio of the air intake area of ​​the contraction section 2 to the throat section 3 is 2-4:1.

[0051] The throttling test method for combustion chamber pressure regulation of this embodiment includes the following steps:

[0052] S10. Install throttling device;

[0053] The throttling device is connected to the combustion chamber through the front flange 7 and the rear flange 8 arranged in front and back; the combustion chamber is an engine combustion chamber or a burner combustion chamber;

[0054] S20. Connect the air source and the regulating valve;

[0055] The air inlet 9 of the throttling device is connected to the air source through an air flow pipeline, and a stop valve and a regulating valve are arranged on the air flow pipeline; the pressure of the air source is more than twice the maximum pressure of the combustion chamber in the test, and the air mass of the air source is more than three times the total mass of air consumed during the test time;

[0056] S30. Calculate the air flow corresponding to the expected combustion chamber pressure;

[0057] Calculate the air flow rate corresponding to the expected combustion chamber pressure in the test , find the throttling characteristic curve of the regulating valve, determine the expected opening corresponding to the regulating valve, and open the regulating valve to the expected opening;

[0058] S40. Start the combustion chamber;

[0059] Start the combustion chamber, and the combustion chamber enters the working state. Measure the actual combustion chamber pressure. If the actual combustion chamber pressure variation range does not exceed ±6% of the expected combustion chamber pressure, start the throttling device test.

[0060] S50 supply air and adjust the air flow according to the combustion chamber pressure;

[0061] Adjust the opening of the air control valve to change the air flow rate, compare and feedback control the actual combustion chamber pressure with the expected combustion chamber pressure; continue to adjust the opening of the air control valve to control the deviation between the actual combustion chamber pressure and the expected combustion chamber pressure within ±2%, and record the adjustment time of the air control valve. If the adjustment time is less than or equal to 0.5s, the throttling device achieves the expected effect.

[0062] Furthermore, the air flow The calculation process is as follows:

[0063] S31. Assume that the flow area of ​​the throat section 3 of the throttling device is A t , the gas flow rate is , gas temperature is , the air temperature is , , then according to the energy conservation principle before and after the gas and air are mixed, the average temperature of the mixed gas after mixing is obtained T m :

[0064] ;

[0065] In the formula, , and Represent gas, air and mixed gas respectively. , and They represent the specific enthalpy of gas, air and mixed gas at the corresponding temperature. When the temperature and gas composition are known, they can be obtained by looking up the Jnaff table. , and The value of the mixed gas after mixing is obtained T m ;

[0066] ;

[0067] In the formula, is the expected combustion chamber pressure, is the gas specific heat ratio, is the gas constant.

[0068] Although the embodiments of the present invention have been disclosed as above, they are not limited to the applications listed in the specification and implementation modes. For those familiar with the art, all features disclosed in the present invention, or steps in all methods or processes disclosed, except for mutually exclusive features and / or steps, can be combined in any way without departing from the principles of the present invention. The present invention is not limited to the specific details and illustrations shown and described herein.

Claims

1. A throttling device for regulating the combustion chamber pressure, characterized in that: The throttling device comprises a contraction section (2), a throat section (3) and an expansion section (6) which are sequentially connected from front to back; A plurality of water cooling channels (4) are arranged in sequence along the central axis in the wall surfaces of the contraction section (2), the throat section (3) and the expansion section (6), the water cooling channels (4) being close to the inner wall surface, and each water cooling channel (4) being connected to a water inlet (10); an annular air replenishing cavity (5) is also arranged, the air replenishing cavity (5) being close to the outer wall surface, and the air replenishing cavity (5) being connected to the air inlet (9); A plurality of groups of air inlet channels are arranged in the wall surface of the contraction section (2) and the throat section (3) and are sequentially distributed along the central axis. The air inlet channels and the water cooling channels (4) are staggeredly distributed. Each group of air inlet channels includes a plurality of wall air inlet holes (1) uniformly distributed along the circumferential direction. Each wall air inlet hole (1) is connected to the air replenishment cavity (5).

2. The throttling device for combustion chamber pressure regulation according to claim 1, characterized in that: The throttling device is used for two types of tests. One type is to provide different combustion chamber pressures in different vehicle tests; the other type is to dynamically change the combustion chamber pressure in a single test.

3. The throttling device for combustion chamber pressure regulation according to claim 1, characterized in that: The throttling device is manufactured by a 3D additive printing method.

4. The throttling device for combustion chamber pressure regulation according to claim 1, characterized in that: The front end of the throttling device is provided with a front flange (7), and the rear end is provided with a rear flange (8).

5. The throttling device for combustion chamber pressure regulation according to claim 1, characterized in that: The diameter of the wall air inlet holes (1) ranges from 1 mm to 4 mm, and the ratio of the hole spacing to the hole diameter is (1-3):

1.

6. The throttling device for combustion chamber pressure regulation according to claim 1, characterized in that: The ratio of the air intake area of ​​the contraction section (2) to the throat section (3) is (2-4):

1.

7. A throttling test method for combustion chamber pressure regulation, which is used for a throttling device for combustion chamber pressure regulation as claimed in any one of claims 1 to 6, characterized in that: The following steps are involved: S10. Install throttling device; The throttling device is connected to the combustion chamber through a front flange (7) and a rear flange (8) arranged at the front and rear ends; the combustion chamber is an engine combustion chamber or a burner combustion chamber; S20. Connect the air source and the regulating valve; The air inlet (9) of the throttling device is connected to an air source through an air flow pipeline, and a stop valve and a regulating valve are provided on the air flow pipeline; the pressure of the air source is more than twice the maximum pressure of the combustion chamber during the test, and the air mass of the air source is more than three times the total mass of air consumed during the test time; S30. Calculate the air flow corresponding to the expected combustion chamber pressure; Calculate the air flow rate corresponding to the expected combustion chamber pressure in the test , find the throttling characteristic curve of the regulating valve, determine the expected opening corresponding to the regulating valve, and open the regulating valve to the expected opening; S40. Start the combustion chamber; Start the combustion chamber, and the combustion chamber enters the working state. Measure the actual combustion chamber pressure. If the actual combustion chamber pressure variation range does not exceed ±6% of the expected combustion chamber pressure, start the throttling device test. S50 supply air and adjust the air flow according to the combustion chamber pressure; Adjust the opening of the air control valve to change the air flow rate, compare and feedback control the actual combustion chamber pressure with the expected combustion chamber pressure; continue to adjust the opening of the air control valve to control the deviation between the actual combustion chamber pressure and the expected combustion chamber pressure within ±2%, and record the adjustment time of the air control valve. If the adjustment time is less than or equal to 0.5s, the throttling device achieves the expected effect.

8. The throttling test method for combustion chamber pressure regulation according to claim 7, characterized in that: The air flow rate The calculation process is as follows: S31. Assume that the flow area of ​​the throat section (3) of the throttling device is A t , the gas flow rate is , gas temperature is , the air temperature is , , then according to the energy conservation principle before and after the gas and air are mixed, the average temperature of the mixed gas after mixing is obtained T m : ； In the formula, , and Represent gas, air and mixed gas respectively. , and They represent the specific enthalpy of gas, air and mixed gas at the corresponding temperature. When the temperature and gas composition are known, they can be obtained by looking up the Jnaff table. , and The value of the mixed gas after mixing is obtained T m ; S32. Calculate the air flow rate using the one-dimensional air flow blockage formula : ； In the formula, is the expected combustion chamber pressure, is the gas specific heat ratio, is the gas constant.

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