Variable-stage steam-jet pump system and control method thereof

Abstract

The invention relates to a steam-jet pump system and a control method thereof, in particular to a variable-stage steam-jet pump system and a control method thereof, and solves the technical problems that an existing steam-jet pump system is difficult to realize switching of different working conditions and energy consumption is difficult to reduce. The variable-stage steam jet pump system comprises a gas collecting chamber and a gas jet pump unit connected with the gas collecting chamber, and the gas jet pump unit comprises a vacuum suction pipeline, a first-stage vacuum jet pump, a first-stage condenser, a second-stage vacuum jet pump, a second-stage condenser and a third-stage vacuum jet pump which are sequentially connected with the gas collecting chamber in the gas flow direction. The system further comprises a three-stage variable pump, a four-stage vacuum jet pump, a steam conveying unit and a cooling water conveying unit. The water supply reliability is greatly improved, and the long-time operation stability of the steam-jet pump system is guaranteed. According to the control method, ignition tests of engines with multiple thrust magnitudes and multiple working heights can be completed.

Description

Technical Field

[0001] The invention relates to a steam jet pump system and a control method thereof, and in particular to a variable-stage steam jet pump system and a control method thereof. Background Art

[0002] The steam jet pump system is mainly used for the suction and exhaust of high-enthalpy turbulent combustion gases formed by the engine jet and high-speed incoming flow. Its main function is to accelerate the high-temperature and high-pressure power steam (energy medium) to a supersonic state, and discharge the test air flow in the upstream vacuum pipe through momentum exchange, so as to maintain a high vacuum degree in the vacuum pipe, thereby ensuring the vacuum degree during the engine test.

[0003] For attitude and orbit control engines or space-grade liquid power systems of manned spacecraft (such as moon landing and Mars exploration), it is necessary to simulate the vacuum environment in space during the ground test phase. For the establishment and long-term maintenance of the space environment, especially for the ignition test of large thrust engines, active ejection is currently used, that is, a steam jet pump system is established to maintain the vacuum degree during engine ignition. Due to the different thrust levels, flow rates and working altitudes (vacuum degrees) of engines, how to establish a steam jet pump system to meet the high-altitude simulated ignition test of engines with different thrust levels and different working altitudes (vacuum degrees), realize the switching of different working conditions, reduce energy consumption while meeting the test requirements, and achieve better environmental protection effects, is an urgent problem to be solved. Summary of the invention

[0004] The purpose of the present invention is to solve the technical problem that the existing steam jet pump system is difficult to switch between different working conditions and reduce energy consumption, and to provide a variable-stage steam jet pump system and a control method thereof.

[0005] In order to achieve the above object, the present invention adopts the following technical solution:

[0006] A variable-stage steam jet pump system, which is special in that it includes a gas collecting chamber, a gas jet pump unit connected to the gas collecting chamber, the gas jet pump unit includes a vacuum suction pipeline connected to the gas collecting chamber in sequence along the gas flow direction, a first-stage vacuum jet pump, a first-stage condenser, a second-stage vacuum jet pump, a second-stage condenser, a third-stage vacuum jet pump, a third-stage variable pump, a fourth-stage vacuum jet pump, a steam delivery unit, and a cooling water delivery unit;

[0007] The gas collecting chamber is used to collect and distribute the gas. The gas collecting chamber is provided with an inlet 101 and an outlet. The inlet is used to connect with an external engine gas equipment, and the outlet is connected with a vacuum suction pipeline and a first vacuum isolation valve is provided at the connection.

[0008] The inlet of the four-stage vacuum jet pump is connected to the outlet of the gas collecting chamber and a second vacuum isolation valve is provided at the connection, and the outlet of the four-stage vacuum jet pump is connected to the inlet of the first-stage vacuum jet pump; the three-stage variable pump is connected to the second-stage condenser and a third vacuum isolation valve is provided at the connection, and the outlet of the three-stage variable pump and the outlet of the three-stage vacuum jet pump are both connected to the atmosphere;

[0009] The steam delivery unit inlet is used to connect with the external power steam supply equipment, and the outlet is respectively connected with the first-stage vacuum jet pump, the second-stage vacuum jet pump, the third-stage vacuum jet pump, the third-stage variable pump, and the fourth-stage vacuum jet pump, so as to deliver the power steam to each stage of the vacuum jet pumps; and a first steam isolation valve is provided between the steam delivery unit outlet and the third-stage variable pump, and a third steam isolation valve is provided between the steam delivery unit outlet and the fourth-stage vacuum jet pump; the vacuum jet pumps at each stage are used to accelerate the power steam to a supersonic state, and to draw the cooled steam to complete the injection of the engine fuel gas;

[0010] The inlet of the cooling water delivery unit is used to connect to an external cooling water source, and the outlet is connected to the primary condenser and the secondary condenser respectively, so as to cool the condensable part of the mixed gas of fuel gas and steam and thus reduce the suction load of the subsequent vacuum jet pump; the primary condenser and the secondary condenser are both used to connect to the external cooling water pool to form a water seal and thus maintain the vacuum degree inside;

[0011] The first vacuum isolation valve, the second vacuum isolation valve, the third vacuum isolation valve, the first steam isolation valve and the third steam isolation valve are all used for being electrically connected to the engine control console.

[0012] Furthermore, the first-stage vacuum jet pump comprises a mixing chamber and a diffuser pipe connected in sequence along the flow direction of the fuel gas; the mixing chamber is used to fully mix the fuel gas and the power steam to form a mixed gas;

[0013] The mixing chamber is provided with a gas suction port and a steam introduction pipe;

[0014] One end of the steam introduction pipe is located outside the mixing chamber and connected to the outlet of the steam delivery unit; the other end of the steam introduction pipe is located inside the mixing chamber and a nozzle is provided at the end thereof;

[0015] The end of the diffuser pipe is set as the outlet of the jet pump and connected to the primary condenser;

[0016] The structures of the secondary vacuum jet pump, the tertiary vacuum jet pump, the tertiary variable pump and the quaternary vacuum jet pump are all the same as that of the primary vacuum jet pump; the jet pump outlet of the secondary vacuum jet pump is connected to the secondary condenser, the jet pump outlet of the tertiary vacuum jet pump is connected to the atmosphere, the jet pump outlet of the tertiary variable pump is connected to the atmosphere, and the jet pump outlet of the quaternary vacuum jet pump is connected to the gas suction port of the primary vacuum jet pump.

[0017] Furthermore, the primary condenser comprises a condenser support skirt, a condenser body arranged on the condenser support skirt, a condenser gas outlet arranged on the condenser body, an upper water inlet pipe of the condenser, a lower water inlet pipe of the condenser, a condenser gas inlet, a gas distributor and an atmospheric condensate pipeline;

[0018] The outlet end of the upper water inlet pipe of the condenser and the outlet end of the lower water inlet pipe of the condenser are respectively arranged inside the upper end of the condenser body, the inlet end of the upper water inlet pipe of the condenser and the inlet end of the lower water inlet pipe of the condenser are located outside the upper end of the condenser body and connected to the cooling water delivery unit through a flow orifice plate, and the upper water inlet pipe of the condenser and the lower water inlet pipe of the condenser are both provided with a spray head with an opening facing downward;

[0019] The condenser gas outlet is arranged at the upper end of the condenser body and connected to the secondary vacuum jet pump; the condenser gas inlet is arranged on the side wall of the lower end of the condenser body and connected to the primary vacuum jet pump;

[0020] One end of the atmospheric condensate pipeline is arranged at the lower end of the condenser body and located inside the condenser support skirt, and the other end is located outside the condenser support skirt, which is used to connect with the external cooling water pool to form a water seal and thus maintain the vacuum degree inside;

[0021] The gas distributor is arranged inside the condenser support skirt and is located above the gas inlet of the condenser;

[0022] The structure of the secondary condenser is the same as that of the primary condenser. The condenser gas inlet of the secondary condenser is connected to the secondary vacuum jet pump. Two condenser gas outlets are arranged on the secondary condenser. The two condenser gas outlets are respectively connected to the tertiary vacuum jet pump and the tertiary variable pump.

[0023] Further, the steam delivery unit comprises a steam main pipeline, a heat accumulator, a steam distributor and a plurality of steam delivery pipelines connected in sequence along the flow direction of the motive steam;

[0024] The steam main pipeline inlet is connected to the external power steam supply equipment;

[0025] The outlet of the steam delivery pipeline is connected to one end of the steam inlet pipe of each stage of the vacuum jet pump.

[0026] Furthermore, the invention also includes a first water inlet valve, a second water inlet valve, a third water inlet valve and a fourth water inlet valve which are electrically connected to the engine control console respectively;

[0027] The cooling water delivery unit includes a cooling water collecting pipe, a cooling water main water supply pipe, a cooling water distributor, and an electromagnetic flowmeter which are sequentially connected along the cooling water flow direction; the electromagnetic flowmeter is arranged on the cooling water main water supply pipe and is electrically connected to the engine control console;

[0028] The cooling water header inlet is used to connect to an external cooling water source;

[0029] The cooling water distributor inlet is connected to the cooling water main supply pipe through the first water inlet valve, the second water inlet valve, the third water inlet valve and the fourth water inlet valve; the cooling water distributor outlet is respectively connected to the condenser upper water inlet pipe and the condenser lower water inlet pipe of the first-stage condenser, and the condenser upper water inlet pipe and the condenser lower water inlet pipe of the second-stage condenser.

[0030] Furthermore, the gas collecting chamber is provided with four inlets and six outlets; the four inlets are used to connect with the gas equipment of the external engine; the six outlets are divided into three groups, which are used to connect with three groups of steam jet pump units; one of the outlets in each group is connected to the vacuum suction pipeline of the corresponding steam jet pump unit, and the other outlet is connected to the corresponding four-stage vacuum jet pump;

[0031] The first-stage vacuum jet pump, the second-stage vacuum jet pump, the third-stage vacuum jet pump, the third-stage variable displacement pump and the fourth-stage vacuum jet pump of each steam jet pump unit are all arranged at an angle.

[0032] Furthermore, the diffuser tube includes a convergent section, a cylindrical section and an expansion section which are sequentially connected along the flow direction of the mixed gas, the convergent section is connected to the mixing chamber, and the jet pump outlet is arranged at the end of the expansion section.

[0033] Furthermore, the method further comprises a second steam isolation valve disposed between the outlet of the steam delivery unit and the three-stage variable pump, and a fourth steam isolation valve disposed between the outlet of the steam delivery unit and the four-stage vacuum ejector pump;

[0034] The second steam isolation valve is located upstream of the first steam isolation valve;

[0035] The fourth steam isolation valve is located upstream of the third steam isolation valve.

[0036] Furthermore, the gas collecting chamber is a single-layer cylinder structure, and its design temperature is 300°C;

[0037] The first vacuum isolation valve, the second vacuum isolation valve and the third vacuum isolation valve are all butterfly valves, using electromagnetic pneumatic control valves, with a design pressure of 0.1MPa and a design temperature of 300℃; the diameters of the first vacuum isolation valve and the second vacuum isolation valve are both DN2000; the diameter of the third vacuum isolation valve is DN600;

[0038] The first steam isolation valve and the third steam isolation valve are both stop valves, using electromagnetic pneumatic control valves, with a design pressure of 2.5MPa, a design temperature of 300℃, and a diameter of DN200;

[0039] The second steam isolation valve and the fourth steam isolation valve are both manual stop valves, and their diameters are both DN200;

[0040] The diameters of the first water inlet valve, the second water inlet valve and the third water inlet valve are all DN600; the diameter of the fourth water inlet valve is DN200.

[0041] At the same time, the present invention also provides a control method for the above variable-stage steam jet pump system, which is special in that it includes the following steps:

[0042] When the engine ignition test starts, the third-level working mode is controlled to be turned on during the engine ignition gap to complete the engine gas injection; or, the third-level working mode is controlled to be turned on during the engine ignition gap, and the third-level working mode is switched to the fourth-level working mode to complete the engine gas injection;

[0043] To open the three-level working mode:

[0044] The first vacuum isolation valve, the third vacuum isolation valve, the first steam isolation valve, the steam delivery unit and the cooling water delivery unit are controlled to be opened, and the second vacuum isolation valve and the third steam isolation valve are closed; at this time, the fuel gas flows from the gas collecting chamber to the vacuum suction pipeline, the first vacuum jet pump, the first condenser, the second vacuum jet pump, the second condenser, the third vacuum jet pump and the third variable pump; at the same time, the power steam is delivered to the first vacuum jet pump, the second vacuum jet pump, the third vacuum jet pump and the third variable pump respectively through the steam delivery unit; the cooling water is delivered to the first condenser and the second condenser through the cooling water delivery unit to cool the condensable part of the mixed gas of the fuel gas and the steam; the first vacuum jet pump, the second vacuum jet pump, the third vacuum jet pump and the third variable pump accelerate the power steam to a supersonic state, and draw the cooled steam to complete the injection of the engine fuel gas;

[0045] The specific steps to switch the third-level working mode to the fourth-level working mode are as follows:

[0046] The first vacuum isolation valve, the third vacuum isolation valve and the first steam isolation valve are controlled to be closed, and the second vacuum isolation valve and the third steam isolation valve are controlled to be opened; at this time, the fuel gas flows from the gas collecting chamber to the fourth-stage vacuum jet pump, the first-stage vacuum jet pump, the first-stage condenser, the second-stage vacuum jet pump, the second-stage condenser, and the third-stage vacuum jet pump; at the same time, the motive steam is respectively transported to the first-stage vacuum jet pump, the second-stage vacuum jet pump, the third-stage vacuum jet pump and the fourth-stage vacuum jet pump through the steam delivery unit; the cooling water is transported to the first-stage condenser and the second-stage condenser through the cooling water delivery unit to cool the condensable part of the mixed gas of the fuel gas and the steam; the first-stage vacuum jet pump, the second-stage vacuum jet pump, the third-stage vacuum jet pump and the fourth-stage vacuum jet pump accelerate the motive steam to a supersonic state, and draw the cooled steam to complete the injection of the engine fuel gas.

[0047] Beneficial effects of the present invention:

[0048] 1. A variable-stage steam jet pump system of the present invention realizes dynamic distribution of steam flow by real-time remote control of vacuum isolation valves (i.e., the first vacuum isolation valve, the second vacuum isolation valve, and the third vacuum isolation valve) and steam isolation valves (i.e., the first steam isolation valve and the third steam isolation valve). By switching between a three-stage variable pump, a four-stage vacuum jet pump, a vacuum isolation valve, and a steam isolation valve, the stage of the steam jet pump is changed (switching between a three-stage working mode and a four-stage working mode), thereby providing different vacuum pressure conditions, and realizing high-altitude simulation tests of engines with different thrust levels and different working altitudes while keeping the total amount of energy medium unchanged.

[0049] 2. The present invention provides a variable-stage steam jet pump system, in which the cooling water delivery unit adopts a valve (i.e., a first water inlet valve, a second water inlet valve, a third water inlet valve, and a fourth water inlet valve) water supply method. Through the redundant backup design, the water supply reliability is greatly improved, ensuring the long-term operation stability of the steam jet pump system.

[0050] 3. The variable-stage steam jet pump system of the present invention can be set with multiple parallel working modes. Different combinations can be formed by remotely controlling the cutting off and opening of the vacuum isolation valve to realize the high-altitude simulation test of the engine within a wide range of working conditions, that is, to realize the pumping and injection of (0-90) kN engine gas, thereby further effectively utilizing energy.

[0051] 4. The present invention provides a variable-stage steam jet pump system, in which a flow orifice plate is arranged at the inlet of the condenser (the first-stage condenser and the second-stage condenser), so as to adjust the flow ratio, reduce the operational difficulty of valve adjustment, and improve convenience and operational reliability.

[0052] 5. The control method of the variable-stage steam jet pump system of the present invention forms a complete set of work processes, which can realize the creation and maintenance of different vacuum degrees and complete the ignition test of engines with various thrust levels and working altitudes.

[0053] 6. The present invention provides a control method for a variable-stage steam jet pump system, which realizes long-term vacuum maintenance during high-altitude simulation tests of engines with different thrust levels and different working altitudes by switching between three-stage and four-stage working modes of the steam jet pump system and operating multiple groups of steam jet pumps in parallel. This method can be applied to similar test requirements of other products, significantly improving the capabilities. BRIEF DESCRIPTION OF THE DRAWINGS

[0054] Figure 1 It is a structural schematic diagram of an embodiment of a variable-stage steam jet pump system of the present invention;

[0055] Figure 2 It is a structural schematic diagram of a first-stage vacuum jet pump in an embodiment of a variable-stage steam jet pump system of the present invention;

[0056] Figure 3 It is a structural schematic diagram of a primary condenser in an embodiment of a variable-stage steam jet pump system of the present invention;

[0057] Figure 4 It is a structural schematic diagram of a steam delivery unit in an embodiment of a variable-stage steam jet pump system of the present invention;

[0058] Figure 5 It is a schematic structural diagram of a cooling water delivery unit and a cooling water supply valve group in an embodiment of a variable-stage steam jet pump system of the present invention;

[0059] Figure 6 It is a schematic structural diagram of three groups of variable-stage steam jet pump units in an embodiment of the variable-stage steam jet pump system of the present invention.

[0060] Description of reference numerals:

[0061] 1-gas collecting chamber, 101-inlet, 102-outlet, 2-vacuum suction pipeline, 3-first-stage vacuum jet pump, 31-gas suction port, 32-mixing chamber, 33-nozzle, 34-steam inlet pipe, 35-diffuser, 36-jet pump outlet, 4-second-stage vacuum jet pump, 5-third-stage vacuum jet pump, 6-third-stage variable pump, 7-fourth-stage vacuum jet pump, 8-first-stage condenser, 81-atmospheric condensate pipeline, 82-condenser gas inlet, 83-condenser gas outlet, 84-condenser lower water inlet pipe, 85-condenser upper water inlet pipe, 86-flow orifice plate, 87-sprinkler head, 88-condenser support skirt, 89-gas distributor, 9-second-stage condenser, 1 0-first vacuum isolation valve, 11-second vacuum isolation valve, 12-third vacuum isolation valve, 13-first steam isolation valve, 14-second steam isolation valve, 15-third steam isolation valve, 16-fourth steam isolation valve, 17-cooling water supply valve group, 171-first water inlet valve, 172-second water inlet valve, 173-third water inlet valve, 174-fourth water inlet valve, 18-steam delivery unit, 181-steam main pipeline, 182-heat accumulator, 183-steam distributor, 184-steam delivery pipeline, 19-cooling water delivery unit, 191-cooling water collecting pipe, 192-cooling water main supply pipe, 193-electromagnetic flowmeter, 194-cooling water distributor. DETAILED DESCRIPTION

[0062] like Figure 1As shown, a variable-stage steam jet pump system includes an air collecting chamber 1, a vacuum suction pipeline 2, a first-stage vacuum jet pump 3, a second-stage vacuum jet pump 4, a third-stage vacuum jet pump 5, a third-stage variable pump 6, a fourth-stage vacuum jet pump 7, a first-stage condenser 8, a second-stage condenser 9, a first vacuum isolation valve 10, a second vacuum isolation valve 11, a third vacuum isolation valve 12, a first steam isolation valve 13, a second steam isolation valve 14, a third steam isolation valve 15, a fourth steam isolation valve 16, a cooling water supply valve group 17, a steam delivery unit 18, a cooling water delivery unit 19, and a cooling water supply valve group 17; the cooling water supply valve group 17 includes a first water inlet valve 171, a second water inlet valve 172, a third water inlet valve 173 and a fourth water inlet valve 174.

[0063] The gas collecting chamber 1 is used to collect and distribute gas. The gas collecting chamber 1 is provided with an inlet 101 and an outlet 102. The inlet 101 is used to connect with external engine gas equipment, and the outlet 102 is connected with the vacuum suction pipe 2. A first vacuum isolation valve 10 is provided between the outlet 102 and the vacuum suction pipe 2. The gas collecting chamber 1 mainly collects and redistributes the incoming engine gas or mixed gas. It is a single-layer cylinder structure with a design temperature of 300°C. The vacuum suction pipe 2 is used to connect the gas collecting chamber 1 and the first-stage jet vacuum pump 3. The pipe diameter is consistent with the suction port diameter of the first-stage vacuum jet pump 3. The pipe length and direction are set according to the arrangement of the first-stage jet vacuum pump 3.

[0064] The gas suction port 31 of the four-stage vacuum jet pump 7 is connected to the outlet 102 of the gas collecting chamber 1 through the second vacuum isolation valve 11, and the outlet of the four-stage vacuum jet pump 7 is connected to the inlet of the first-stage vacuum jet pump 3; a third vacuum isolation valve 12 is arranged between the inlet of the three-stage variable pump 6 and the condenser gas outlet 82 of the second-stage condenser 8, and the outlet of the three-stage variable pump 6 and the outlet of the three-stage vacuum jet pump 5 are both connected to the atmosphere; each stage of the vacuum jet pump provides a gas channel and a steam channel, and realizes mixed suction with the incoming gas through the injection of power steam. In order to effectively utilize the space, the vacuum jet pumps of each stage are arranged obliquely, and the vacuum jet pumps of each stage are arranged in series with each other to realize the continuous injection of the incoming gas and finally discharge it into the atmosphere; condensers can be set between the vacuum jet pumps of each stage, and the steam flow of the three-stage vacuum jet pump 5 is scientifically calculated to distribute the steam flow, and is divided into a large pump and a small pump (i.e., the three-stage variable pump 6). The three-stage and four-stage working modes of the steam jet pump system can be realized by switching the working mode of the variable pump, thereby providing different ultimate vacuum degrees and ignition vacuum degrees.

[0065] The inlet of the steam delivery unit 18 is used to connect to an external power steam supply device, and the outlet is respectively connected to the first-stage vacuum jet pump 3, the second-stage vacuum jet pump 4, the third-stage vacuum jet pump 5, the third-stage variable pump 6, and the fourth-stage vacuum jet pump 7, so as to deliver the power steam to each stage of the vacuum jet pumps; and a first steam isolation valve 13 is provided between the inlet of the steam delivery unit 18 and the third-stage variable pump 6, and a third steam isolation valve 15 is provided between the inlet of the steam delivery unit 18 and the fourth-stage vacuum jet pump 7; the vacuum jet pumps at each stage are used to accelerate the power steam to a supersonic state and to draw the cooled steam to complete the injection of the engine fuel gas; the inlet of the cooling water delivery unit 19 is used to connect to an external cooling water source, and the outlet is respectively connected to the first The condenser 8 and the secondary condenser 9 are connected to cool the condensable part of the mixed gas of fuel gas and steam so as to reduce the suction load of the subsequent vacuum jet pump; the primary condenser 8 and the secondary condenser 9 are both used to connect with the external cooling water pool to form a water seal so as to maintain the vacuum degree inside; a second steam isolation valve 14 is arranged between the inlet of the steam delivery unit 18 and the third-stage variable pump 6, and a fourth steam isolation valve 16 is arranged between the inlet of the steam delivery unit 18 and the fourth-stage vacuum jet pump 7; the second steam isolation valve 14 is located upstream of the first steam isolation valve 13; the fourth steam isolation valve 16 is located upstream of the third steam isolation valve 15; under normal circumstances, the second steam isolation valve 14 and the fourth steam isolation valve 16 are in an open state.

[0066] The first vacuum isolation valve 10, the second vacuum isolation valve 11, the third vacuum isolation valve 12, the first steam isolation valve 13 and the third steam isolation valve 15 are all used to be electrically connected to the engine control console. The opening or cutting off of the first vacuum isolation valve 10, the second vacuum isolation valve 11 and the third vacuum isolation valve 12 can realize the opening of the gas suction channel, and at the same time realize the test requirements of engines of different thrust levels. Preferably, the first vacuum isolation valve 10, the second vacuum isolation valve 11 and the third vacuum isolation valve 12 are all butterfly valves, using electromagnetic pneumatic control valves, and their design pressures are all 0.1MPa and their design temperatures are all 300℃; the diameters of the first vacuum isolation valve 10 and the second vacuum isolation valve 11 are both DN2000; the diameter of the third vacuum isolation valve 12 is DN600; the first vacuum isolation valve 10 connects or cuts off the gas collecting chamber 1 and the vacuum suction pipeline 2, and the gas can enter the vacuum suction pipeline 2 through the first vacuum isolation valve 10, and then enter the steam jet pump for continuous injection. By switching the first vacuum isolation valve 10, the redistribution of the incoming gas can be achieved to meet the ignition requirements and vacuum injection of different thrust conditions of the engine. The second vacuum isolation valve 11 is located between the three-stage variable pump 6 and the secondary condenser 9, and is mainly used to cut off or connect the gas channel of the three-stage variable pump 6. The third vacuum isolation valve 12 is located between the four-stage vacuum jet pump 7 and the vacuum suction pipeline 2. It forms a parallel channel with the first vacuum isolation valve 10, and is mainly used to cut off or connect the gas channel of the four-stage vacuum jet pump 7.

[0067] The first steam isolation valve 13 and the third steam isolation valve 15 are both stop valves, which adopt electromagnetic pneumatic control valves, with a design pressure of 2.5MPa, a design temperature of 300℃, and a diameter of DN200; the second steam isolation valve 14 and the fourth steam isolation valve 16 are both manual stop valves, with a diameter of DN200; the diameters of the first water inlet valve 171, the second water inlet valve 172, and the third water inlet valve 173 are all DN600; the diameter of the fourth water inlet valve 174 is DN200. The first steam isolation valve 13 can realize the cut-off and isolation of the three-stage variable pump 6 and the steam delivery unit 18. The second steam isolation valve 14 is arranged in front of the first steam isolation valve 14 to manually cut off and open the steam pipeline channel of the three-stage variable pump 6. The third steam isolation valve 15 can realize the cut-off and isolation of the four-stage vacuum jet pump 7 and the steam delivery unit 18. The steam supply can be switched by remote online switching of the steam isolation valve, and the corresponding jet pump can be switched and started at the same time, so as to realize the conversion of different working conditions.

[0068] like Figure 2 As shown, the first-stage vacuum jet pump 3 includes a mixing chamber 32 and a diffuser 35 which are sequentially connected along the flow direction of the gas; the mixing chamber 32 is used to fully mix the gas and the power steam to form a mixed gas; the mixing chamber 32 is provided with a gas suction port 31 and a steam inlet pipe 34; one end of the steam inlet pipe 34 is located outside the mixing chamber 32 and is connected to the outlet of the steam delivery unit 18; the other end of the steam inlet pipe 34 is located in the mixing chamber 32, and a nozzle 33 is provided at its end; the diffuser 35 includes a convergent section, a cylindrical section and an expansion section which are sequentially connected along the flow direction of the mixed gas, and the expansion section is provided with a jet pump outlet 36 which is connected to the first-stage condenser 8. The structures of the secondary vacuum jet pump 4, the tertiary vacuum jet pump 5, the tertiary variable pump 6, and the quaternary vacuum jet pump 7 are the same as those of the primary vacuum jet pump 3; the jet pump outlet 36 of the secondary vacuum jet pump 4 is connected to the secondary condenser 9, the jet pump outlet 36 of the tertiary vacuum jet pump 5 is connected to the atmosphere, the jet pump outlet 36 of the tertiary variable pump 6 is connected to the atmosphere, and the jet pump outlet 36 of the quaternary vacuum jet pump 7 is connected to the gas suction port 31 of the primary vacuum jet pump 3. The nozzle 33 mainly introduces motive steam, the mixing chamber 32 is a gas and motive steam mixing zone, and the diffuser 35 is a mixed gas pressure increase and deceleration zone, which requires the steam delivery system 18 to supply steam.

[0069] like Figure 3As shown, the primary condenser 8 includes a condenser support skirt 88, a condenser body arranged on the condenser support skirt 88, a condenser upper water inlet pipe 85 arranged on the condenser body, a condenser lower water inlet pipe 84, a condenser gas inlet 82, a gas distributor 89 and an atmospheric condensate pipeline 81; one end of the condenser upper water inlet pipe 85 and one end of the condenser lower water inlet pipe 84 are respectively arranged inside the condenser support skirt 88, the other end of the condenser upper water inlet pipe 85 and the other end of the condenser lower water inlet pipe 84 are located outside the upper end of the condenser body and connected to the cooling water delivery unit 19 through a flow orifice 86, and the condenser upper water inlet pipe 85 and the condenser lower water inlet pipe 84 are both provided with a spray head 87 with an opening facing downward; the condenser gas outlet 83 is arranged at the upper end of the condenser body and connected to the secondary vacuum jet pump 4; the condenser The gas inlet 82 is arranged on the side wall of the lower end of the condenser body and connected to the first-stage vacuum jet pump 3; one end of the atmospheric condensate pipeline 81 is arranged at the lower end of the condenser body and located inside the condenser support skirt 88, and the other end is located outside the condenser support skirt 88, which is used to connect with the external cooling water pool to form a water seal and thus maintain the vacuum degree inside; the gas distributor 89 is arranged inside the condenser support skirt 88 and located above the condenser gas inlet 82, which is used to achieve the flow diversion and uniform distribution of the gas; the structure of the secondary condenser 9 is the same as that of the first-stage condenser 8, and the condenser gas inlet 82 of the secondary condenser 9 is connected to the secondary vacuum jet pump 4, and two condenser gas outlets 83 are arranged on the secondary condenser 9, and the two condenser gas outlets 83 are respectively connected to the third-stage vacuum jet pump 5 and the third-stage variable pump 6. Among them, the third-stage vacuum jet pump 5 and the third-stage variable pump 6 are both led out from the gas outlet above the secondary condenser 9, which is a parallel mode. The primary condenser 8 and the secondary condenser 9 are mainly used to cool the mixed gas at the outlet of the jet pump to reduce the load of the subsequent vacuum jet pump, and they need to be supplied with cooling water by the cooling water delivery unit 19. The direction of the incoming gas flowing through the condenser (primary condenser 8 and secondary condenser 9) is bottom-in and top-out. Water is supplied to the upper and lower spray heads 87 inside the condenser, and the gas is sprayed out through the spray heads 87 to condense the gas.

[0070] like Figure 4As shown, the steam delivery unit 18 mainly delivers motive steam for vacuum jet pumps at various levels, including a steam main pipeline 181, a heat accumulator 182, a steam distributor 183 and a plurality of steam delivery pipelines 184 connected in sequence along the flow direction of motive steam; the inlet of the steam main pipeline 181 is connected to an external motive steam supply device; the outlet of the steam delivery pipeline 184 is connected to one end of the steam introduction pipe 34 of the vacuum jet pumps at various levels. The diameter of the steam main pipeline 181 is DN700, the heat accumulator 182 is a single-layer cylinder structure, which is used to collect the generated steam, and is provided with an inlet and an outlet; the steam distributor 183 is a single-layer cylinder structure, which is provided with an inlet and five outlets (which can be adjusted according to the number of vacuum jet pumps at various levels), the inlet is connected to the outlet of the heat accumulator 182, and the outlet is connected to the steam inlet pipeline of the steam introduction pipe on the vacuum jet pumps at various levels. The overall design pressure of the steam delivery unit 18 is 2.5 MPa, and it is mainly used to deliver the motive steam generated by the external motive steam supply equipment (the absolute pressure of the motive steam used in the present invention is 1.3 MPa, and the steam temperature is 185°C), wherein the diameter of the steam inlet pipe 34 of each stage of the vacuum jet pump is consistent with the inlet diameter of the steam nozzle 33 of each stage of the vacuum jet pump.

[0071] like Figure 5As shown, the cooling water delivery unit 19 mainly delivers cooling water to each stage of condensers, including a cooling water collecting pipe 191, a cooling water main supply pipe 192, a cooling water distributor 194, and an electromagnetic flowmeter 193 which are connected in sequence along the cooling water flow direction; the electromagnetic flowmeter 193 is arranged on the cooling water main supply pipe 192 and is electrically connected to the engine control console; the inlet of the cooling water collecting pipe 191 is used to be connected to an external cooling water source; the inlet of the cooling water distributor 194 is connected to the cooling water main supply pipe 192 through the first inlet valve 171, the second inlet valve 172, the third inlet valve 173 and the fourth inlet valve 174, and the outlet of the cooling water distributor 194 is respectively connected to the condenser upper inlet pipe 85 and the condenser lower inlet pipe 84 of the first-stage condenser 8, and the condenser upper inlet pipe 85 and the condenser lower inlet pipe 84 of the second-stage condenser 9. The diameter of the cooling water collecting pipe 191 is DN2000, the diameter of the cooling water main supply pipe 192 is DN1000, and the cooling water distributor 194 is a single-layer cylindrical structure with four inlets and four outlets (adjustable according to the number of condensers). The overall design pressure of the cooling water delivery unit 19 is 1.6MPa, which is mainly used to deliver cooling water from an external cooling water source, and an electromagnetic flowmeter 193 is set at the inlet. The first water inlet valve 171, the second water inlet valve 172, the third water inlet valve 173 and the fourth water inlet valve 174 are all butterfly valves, which are electrically connected to the engine control console and electrically controlled. They are mainly used to cut off and supply cooling water. The cooling water supply valve group 17 is equipped with 4 electric butterfly valves, of which 1 is DN200 and 3 are DN600. The cooling water enters the cooling water distributor 194 through the cooling water supply valve group 17. The outlet of the cooling water distributor 194 is connected to the upper and lower water inlets of the condenser. The water inlet is designed with a flow orifice 86 to ensure the water inlet ratio of the condenser. The system of the present invention adopts a multi-way parallel water supply method to effectively reduce the impact of water hammer. At the same time, it adopts a redundant backup design to effectively reduce the risk of single point failure and improve the stability and reliability of the system water supply.

[0072] The variable-stage steam jet pump system of the present invention can realize high-altitude simulated ignition tests of engines with different thrusts and different altitudes while keeping the total amount of energy medium unchanged; a plurality of variable-stage steam jet pump systems are arranged, and the switching between the three-stage working mode and the four-stage working mode can be completed through the online switching of the first vacuum isolation valve 10, the second vacuum isolation valve 11, the third vacuum isolation valve 12 and the first steam isolation valve 13, the second steam isolation valve 14, the third steam isolation valve 15, and the fourth steam isolation valve 16, so as to achieve different suction flow and vacuum degree requirements, thereby achieving the purpose of assessment.

[0073] Each level of vacuum jet pump is the core component of the variable-level steam jet pump system, which is mainly used to accelerate the power steam to a supersonic state through the nozzle 33 to complete the injection of the engine gas. The first-stage condenser 8 and the second-stage condenser 9 mainly cool the condensable part of the incoming mixed gas to reduce the suction load of the rear-stage vacuum jet pump. The direction of the incoming gas flowing through the condenser is from bottom to top. The atmospheric condensate pipeline 81 is connected to the external cooling water pool below, which mainly plays the role of vacuum water seal. When the first-stage condenser 8 and the second-stage condenser 9 are vacuum inside, the water in the cooling water pool enters the atmospheric condensate pipeline 81 under the action of atmospheric pressure to form a water seal; the cooling water delivery unit 19 supplies water to the upper and lower spray heads 87 inside the condenser, and the gas is sprayed out through the spray head 87 to condense the gas. The gas distributor 89 is mainly used to achieve the diversion and uniform distribution of the gas. The flow orifice plate 86 is used to adjust and distribute the cooling water flow.

[0074] The cooling water flow rate calculation formula of the flow orifice plate 86 is as follows:

[0075]

[0076] Where: Q is the cooling water flow rate, in kg / s; C is the cooling water flow coefficient, dimensionless; A is the cross-sectional area of ​​the required flow orifice 86, in mm 2 ; ρ is cooling water density, unit is kg / m 3 ; ΔP is cooling water, unit is MPa.

[0077] The first-stage condenser 8 and the second-stage condenser 9 are both in the form of a water supply valve group with a redundant backup design. The water supply pressure is 0.7MPa. A cooling water distributor 194 is set upstream of the condenser to ensure the supply and distribution of cooling water. The cooling water supply valve group 17 is equipped with a total of 4 valves, of which the first water inlet valve 171 and the second water inlet valve 172 are symmetrically arranged to enter the cooling water distributor 194 to reduce the impact of water hammer during the opening of the butterfly valve. The upper and lower water inlets of the condenser are provided with a flow regulating orifice 86 to ensure the upper and lower cooling water flow distribution ratio of the condenser; in the present invention, the aperture of the upper spray head 87 of the first-stage condenser 8 is consistent with the aperture of the lower spray head 87 of the first-stage condenser 8, both of which are Φ210mm, and the aperture of the upper spray head 87 of the second-stage condenser 9 is consistent with the aperture of the upper spray head 87 of the second-stage condenser 9, both of which are Φ190mm.

[0078] During use, the first water inlet valve 171, the second water inlet valve 172, the third water inlet valve 173, and the fourth water inlet valve 174 are used as backup. The water supply valve opening process is as follows:

[0079] Open the fourth water inlet valve 174 for 15 seconds to ensure that the fourth water inlet valve 174 is fully opened. The specific time depends on the action time of the fourth water inlet valve 174. At the same time, open the first water inlet valve 171 and the second water inlet valve 172.

[0080] The water supply valve closing process is as follows:

[0081] Close the first water inlet valve 171 and the second water inlet valve 172 at the same time, with an interval of 30 seconds, to ensure that the first water inlet valve 171 and the second water inlet valve 172 are completely closed. The specific time depends on the action time of the first water inlet valve 171 and the second water inlet valve 172, and then close the fourth water inlet valve 174.

[0082] By adopting the valve arrangement and water supply form of the present invention, the influence of water hammer pressure can be reduced at the moment of valve opening and closing, and the risk of single-point failure of the valve can be reduced by adopting a redundant backup design concept, thereby achieving reliable supply of cooling water.

[0083] like Figure 6 As shown, in order to be applicable to high-altitude simulation tests of engines with a wide range of thrust, a variable-stage steam jet pump system can be set to a plurality of parallel types by setting multiple outlets 102 above the gas collecting chamber 1. In this embodiment, four inlets 101 are set on the gas collecting chamber 1, and the diameter of the inlet 101 is DN3000, and six outlets 102 are set, and the diameter of the outlet 102 is DN2000; the four inlets 101 are used to connect with the gas equipment of the external engine; the inlet 101 and the outlet 102 on the gas collecting chamber 1 can be set according to the number of jet pump groups, and the six outlets 102 are divided into three groups, namely group A, group B and group C, wherein the variable-stage steam jet pump system can be specifically set according to actual conditions, and is used to connect three groups of steam jet pump units; one of the outlets 102 of each group of outlets is connected to the vacuum suction pipe 2 of the corresponding steam jet pump unit, and the other outlet 102 is connected to the corresponding four-stage vacuum jet pump 7.

[0084] When there are three sets of variable-stage steam jet pump units, the first vacuum isolation valves 10 are set to 6 in total, and every two first vacuum isolation valves 10 form a group, which are divided into three groups in total. The second vacuum isolation valves 11 are also set to 6 in total, and every two form a group. The third vacuum isolation valves 12 are set to 3 in total, and each one forms a group. Figure 6 It can be seen that the ultimate vacuum degree of a single set of three variable-stage steam jet pump units in the three-stage working mode can reach 200-300Pa, and the system vacuum degree can be below 1000Pa when the engine with a thrust of 30kN or less is ignited. The three sets can achieve the system vacuum degree of 1000Pa when the engine with a thrust of 90kN or less is ignited. By opening the number of first vacuum isolation valves 10, a combination of multiple modes can be performed, thereby effectively completing the ignition test of engines with different thrust levels, thereby improving energy efficiency.

[0085] Similarly, by Figure 6It can be seen that when a single set of steam jet pumps is in the four-level working mode, the system's ultimate vacuum can reach below 100Pa. When the engine is ignited, the system's vacuum is below 600Pa, which can achieve ignition of engines with a thrust of 10kN or less. Three sets can achieve ignition of engines with a thrust of 30kN or less. By opening the number of second vacuum isolation valves 11, a combination of multiple modes can be performed, thereby effectively completing a wide range of engine ignition tests with different thrust levels, while providing different vacuum levels. A wide range of thrust level engine ignition conditions are achieved.

[0086] At the same time, the present invention also provides a control method for the above variable-stage steam jet pump system, comprising the following steps:

[0087] When the engine ignition test starts, the third-level working mode is controlled to be turned on during the engine ignition gap to complete the engine gas injection; or, the third-level working mode is controlled to be turned on during the engine ignition gap, and the third-level working mode is switched to the fourth-level working mode to complete the engine gas injection;

[0088] To open the three-level working mode:

[0089] The first vacuum isolation valve 10, the third vacuum isolation valve 12, the first steam isolation valve 13, the steam delivery unit 18 and the cooling water delivery unit 19 are controlled to be opened, and the second vacuum isolation valve 11 and the third steam isolation valve 15 are closed; at this time, the gas flows from the gas collecting chamber 1 to the vacuum suction pipeline 2, the first vacuum jet pump 3, the first condenser 8, the second vacuum jet pump 4, the second condenser 9, the third vacuum jet pump 5 and the third variable pump 6; at the same time, the power steam is delivered to the first vacuum jet pump 3, the second vacuum jet pump 4, the third vacuum jet pump 5 and the third variable pump 6 respectively through the steam delivery unit 18; the cooling water is delivered to the first condenser 8 and the second condenser 9 through the cooling water delivery unit 19 to cool the condensable part of the mixed gas of the gas and steam; the first vacuum jet pump 3, the second vacuum jet pump 4, the third vacuum jet pump 5 and the third variable pump 6 accelerate the power steam to a supersonic state, and draw the cooled steam to complete the injection of the engine gas.

[0090] In the three-stage pump working mode, the three-stage variable pump 6 is in working state, and the ultimate vacuum degree of the variable stage steam jet pump system can reach 200-300Pa. When the engine ignition can be maintained, the vacuum degree of the variable stage steam jet pump system is below 1000Pa. A single set of variable stage steam jet pump system can realize the ignition of engines with thrust of 30kN and below.

[0091] The specific steps to switch the third-level working mode to the fourth-level working mode are as follows:

[0092] The second vacuum isolation valve 11 and the third steam isolation valve 15 are controlled to be opened, and the first vacuum isolation valve 10, the third steam isolation valve 12 and the first steam isolation valve 13 are closed; at this time, the gas flows from the gas collecting chamber to the fourth-stage vacuum jet pump 7, the first-stage vacuum jet pump 3, the first-stage condenser 8, the second-stage vacuum jet pump 4, the second-stage condenser 9, and the third-stage vacuum jet pump 5; at the same time, the power steam is respectively transported to the first-stage vacuum jet pump 3, the second-stage vacuum jet pump 4, the third-stage vacuum jet pump 5 and the fourth-stage vacuum jet pump 7 through the steam delivery unit 18; the cooling water is transported to the first-stage condenser 8 and the second-stage condenser 9 through the cooling water delivery unit 19 to cool the condensable part of the mixed gas of the gas and steam; the first-stage vacuum jet pump 3, the second-stage vacuum jet pump 4, the third-stage vacuum jet pump 5 and the fourth-stage vacuum jet pump 7 accelerate the power steam to a supersonic state, and draw the cooled steam to complete the injection of the engine gas.

[0093] In the four-stage pump working mode, the three-stage variable pump 6 is in a stopped state, and the ultimate vacuum degree of the variable-stage steam jet pump system can reach below 100Pa. When the engine ignition can be maintained, the vacuum degree of the variable-stage steam jet pump system is below 700Pa. A single set of steam jet pump system can achieve engine ignition of 10kN thrust and below.

[0094] The switching of the gas channel is controlled by the engine console to achieve remote online switching of the first vacuum isolation valve 10, the second vacuum isolation valve 11, the third vacuum isolation valve 12, the first steam isolation valve 13, and the third steam isolation valve 15, and the opening or closing time is less than 10s. The switching of the power steam is completed by the engine console to control the first steam isolation valve 13, the second steam isolation valve 14, the third steam isolation valve 15, and the fourth steam isolation valve 16, and the opening or closing time is less than 10s. The second steam isolation valve 14 is located upstream of the first steam isolation valve 13, and the fourth steam isolation valve 16 is located upstream of the third steam isolation valve 15, and is mainly used for cutting off or connecting the steam channel. The second steam isolation valve 14 and the fourth steam isolation valve 16 can remain in a normally open state during system use, which is convenient for online real-time switching of system modes.

[0095] To ensure smooth switching of the gas channel and the power steam channel during online switching, it should be performed during the engine ignition interval (i.e., when the engine is not working), first switch the gas channel, and then switch the power steam channel. In this embodiment, the sequence is as follows: first switch the gas channel online, open the second vacuum isolation valve 11, and close the first vacuum isolation valve 10 and the third vacuum isolation valve 12 at the same time; then switch the power steam channel, open the third steam isolation valve 15, and close the first steam isolation valve 13. The two valve action instructions should be issued by the engine control console at the same time to avoid reducing the fluctuation of the upstream power steam pressure.

Claims

1. A variable-stage steam jet pump system, characterized in that: The invention comprises a gas collecting chamber (1), a gas jet pump unit connected to the gas collecting chamber (1), wherein the gas jet pump unit comprises a vacuum suction pipeline (2) connected to the gas collecting chamber (1) in sequence along the gas flow direction, a first-stage vacuum jet pump (3), a first-stage condenser (8), a second-stage vacuum jet pump (4), a second-stage condenser (9), a third-stage vacuum jet pump (5), a third-stage variable displacement pump (6), a fourth-stage vacuum jet pump (7), a steam delivery unit (18), and a cooling water delivery unit (19); The gas collecting chamber (1) is used to collect and distribute gas. An inlet (101) and an outlet (102) are provided on the gas collecting chamber (1). The inlet (101) is used to be connected to an external engine gas equipment. The outlet (102) is connected to a vacuum suction pipeline (2) and a first vacuum isolation valve (10) is provided at the connection. The inlet of the four-stage vacuum jet pump (7) is connected to the outlet (102) of the gas collecting chamber (1), and a second vacuum isolation valve (11) is provided at the connection point; the outlet of the four-stage vacuum jet pump (7) is connected to the inlet of the first-stage vacuum jet pump (3); the three-stage variable pump (6) is connected to the second-stage condenser (9), and a third vacuum isolation valve (12) is provided at the connection point; the outlet of the three-stage variable pump (6) and the outlet of the three-stage vacuum jet pump (5) are both in communication with the atmosphere; The steam delivery unit (18) has an inlet for connecting to an external power steam supply device, and an outlet for connecting to a first-stage vacuum jet pump (3), a second-stage vacuum jet pump (4), a third-stage vacuum jet pump (5), a third-stage variable pump (6), and a fourth-stage vacuum jet pump (7), respectively, for delivering power steam to each stage of the vacuum jet pumps; a first steam isolation valve (13) is provided between the outlet of the steam delivery unit (18) and the third-stage variable pump (6), and a third steam isolation valve (15) is provided between the outlet of the steam delivery unit (18) and the fourth-stage vacuum jet pump (7); and each stage of the vacuum jet pumps is used to accelerate the power steam to a supersonic state and to draw the cooled steam to complete the injection of the engine fuel gas; The inlet of the cooling water delivery unit (19) is used to be connected to an external cooling water source, and the outlet is respectively connected to the primary condenser (8) and the secondary condenser (9), and is used to cool the condensable part of the mixed gas of the fuel gas and the steam, thereby reducing the suction load of the subsequent vacuum jet pump; the primary condenser (8) and the secondary condenser (9) are both used to be connected to an external cooling water pool to form a water seal, thereby maintaining the vacuum degree inside; The first vacuum isolation valve (10), the second vacuum isolation valve (11), the third vacuum isolation valve (12), the first steam isolation valve (13) and the third steam isolation valve (15) are all used for being electrically connected to an engine control console.

2. A variable-stage steam jet pump system according to claim 1, characterized in that: The primary vacuum jet pump (3) comprises a mixing chamber (32) and a diffuser pipe (35) which are sequentially connected along the flow direction of the fuel gas; the mixing chamber (32) is used to fully mix the fuel gas and the motive steam to form a mixed gas; The mixing chamber (32) is provided with a gas suction port (31) and a steam introduction pipe (34); One end of the steam introduction pipe (34) is located outside the mixing chamber (32) and is connected to the outlet of the steam delivery unit (18); the other end of the steam introduction pipe (34) is located inside the mixing chamber (32) and is provided with a nozzle (33) at its end; The end of the diffuser pipe (35) is arranged as a jet pump outlet (36) and connected to a primary condenser (8); The structures of the secondary vacuum jet pump (4), the tertiary vacuum jet pump (5), the tertiary variable pump (6), and the quaternary vacuum jet pump (7) are all the same as the structure of the primary vacuum jet pump (3); the jet pump outlet (36) of the secondary vacuum jet pump (4) is connected to the secondary condenser (9), the jet pump outlet (36) of the tertiary vacuum jet pump (5) is connected to the atmosphere, the jet pump outlet (36) of the tertiary variable pump (6) is connected to the atmosphere, and the jet pump outlet (36) of the quaternary vacuum jet pump (7) is connected to the gas suction port (31) of the primary vacuum jet pump (3).

3. A variable-stage steam jet pump system according to claim 2, characterized in that: The primary condenser (8) comprises a condenser support skirt (88), a condenser body arranged on the condenser support skirt (88), a condenser gas outlet (83) arranged on the condenser body, an upper condenser water inlet pipe (85), a lower condenser water inlet pipe (84), a condenser gas inlet (82), a gas distributor (89) and an atmospheric condensate pipeline (81); The outlet end of the upper water inlet pipe (85) of the condenser and the outlet end of the lower water inlet pipe (84) of the condenser are respectively arranged inside the upper end of the condenser body, the inlet end of the upper water inlet pipe (85) of the condenser and the inlet end of the lower water inlet pipe (84) of the condenser are located outside the upper end of the condenser body and connected to the cooling water delivery unit (19) through a flow orifice plate (86), and the upper water inlet pipe (85) of the condenser and the lower water inlet pipe (84) of the condenser are both provided with a spray head (87) with an opening facing downward; The condenser gas outlet (83) is arranged at the upper end of the condenser body and connected to the secondary vacuum jet pump (4); the condenser gas inlet (82) is arranged on the side wall of the lower end of the condenser body and connected to the primary vacuum jet pump (3); One end of the atmospheric condensate pipeline (81) is arranged at the lower end of the condenser body and located inside the condenser support skirt (88), and the other end is located outside the condenser support skirt (88) and is used to connect with the external cooling water pool to form a water seal and thus maintain the vacuum degree inside. The gas distributor (89) is arranged inside the condenser support skirt (88) and is located above the condenser gas inlet (82); The structure of the secondary condenser (9) is the same as that of the primary condenser (8). The condenser gas inlet (82) of the secondary condenser (9) is connected to the secondary vacuum jet pump (4). The secondary condenser (9) is provided with two condenser gas outlets (83). The two condenser gas outlets (83) are respectively connected to the tertiary vacuum jet pump (5) and the tertiary variable pump (6).

4. A variable-stage steam jet pump system according to claim 3, characterized in that: The steam delivery unit (18) comprises a steam main pipeline (181), a heat accumulator (182), a steam distributor (183) and a plurality of steam delivery pipelines (184) which are sequentially connected along the flow direction of the motive steam; The inlet of the steam main pipeline (181) is connected to an external power steam supply device; The outlet of the steam delivery pipeline (184) is connected to one end of the steam introduction pipe (34) of each stage of the vacuum jet pump.

5. A variable-stage steam jet pump system according to claim 4, characterized in that: It also includes a first water inlet valve (171), a second water inlet valve (172), a third water inlet valve (173) and a fourth water inlet valve (174) which are electrically connected to the engine control console respectively; The cooling water delivery unit (19) comprises a cooling water collecting pipe (191), a cooling water main water supply pipe (192), a cooling water distributor (194), and an electromagnetic flowmeter (193) which are sequentially connected along the cooling water flow direction; the electromagnetic flowmeter (193) is arranged on the cooling water main water supply pipe (192) and is electrically connected to the engine control console; The inlet of the cooling water collecting pipe (191) is used to connect to an external cooling water source; The inlet of the cooling water distributor (194) is connected to the cooling water main supply pipe (192) through the first water inlet valve (171), the second water inlet valve (172), the third water inlet valve (173) and the fourth water inlet valve (174); the outlet of the cooling water distributor (194) is respectively connected to the condenser upper water inlet pipe (85) and the condenser lower water inlet pipe (84) of the first-stage condenser (8), and the condenser upper water inlet pipe (85) and the condenser lower water inlet pipe (84) of the second-stage condenser (9).

6. A variable-stage steam jet pump system according to any one of claims 1 to 5, characterized in that: The gas collecting chamber (1) is provided with four inlets (101) and six outlets (102); the four inlets (101) are used to connect to the gas equipment of an external engine; the six outlets (102) are divided into three groups, which are used to connect to three groups of steam jet pump units; one of the outlets (102) of each group of outlets is connected to the vacuum suction pipeline (2) of the corresponding steam jet pump unit, and the other outlet (102) is connected to the corresponding four-stage vacuum jet pump (7); The first-stage vacuum jet pump (3), the second-stage vacuum jet pump (4), the third-stage vacuum jet pump (5), the third-stage variable displacement pump (6) and the fourth-stage vacuum jet pump (7) of each group of steam jet pump units are all arranged at an angle.

7. A variable-stage steam jet pump system according to claim 6, characterized in that: The diffuser pipe (35) comprises a convergent section, a cylindrical section and an expansion section which are sequentially connected along the flow direction of the mixed gas, the convergent section is connected to the mixing chamber (32), and the jet pump outlet (36) is arranged at the end of the expansion section.

8. A variable-stage steam jet pump system according to claim 7, characterized in that: It also includes a second steam isolation valve (14) arranged between the outlet of the steam delivery unit (18) and the third-stage variable pump (6), and a fourth steam isolation valve (16) between the outlet of the steam delivery unit (18) and the fourth-stage vacuum jet pump (7); The second steam isolation valve (14) is located upstream of the first steam isolation valve (13); The fourth steam isolation valve (16) is located upstream of the third steam isolation valve (15).

9. A variable-stage steam jet pump system according to claim 8, characterized in that: The gas collecting chamber (1) is a single-layer cylindrical structure, and its design temperature is 300°C; The first vacuum isolation valve (10), the second vacuum isolation valve (11) and the third vacuum isolation valve (12) are all butterfly valves, adopting electromagnetic pneumatic control valves, and their design pressures are all 0.1 MPa, and their design temperatures are all 300° C.; the diameters of the first vacuum isolation valve (10) and the second vacuum isolation valve (11) are both DN2000; and the diameter of the third vacuum isolation valve (12) is DN600; The first steam isolation valve (13) and the third steam isolation valve (15) are both stop valves, adopting electromagnetic pneumatic control valves, with a design pressure of 2.5 MPa, a design temperature of 300° C., and a diameter of DN200; The second steam isolation valve (14) and the fourth steam isolation valve (16) are both manual stop valves, and their diameters are both DN200; The diameters of the first water inlet valve (171), the second water inlet valve (172), and the third water inlet valve (173) are all DN600; and the diameter of the fourth water inlet valve (174) is DN200.

10. A control method for a variable-stage steam jet pump system according to any one of claims 1 to 9, characterized in that: The following steps are involved: When the engine ignition test starts, the third-level working mode is controlled to be turned on during the engine ignition gap to complete the engine gas injection; or, the third-level working mode is controlled to be turned on during the engine ignition gap, and the third-level working mode is switched to the fourth-level working mode to complete the engine gas injection; The specific opening of the three-level working mode is: The first vacuum isolation valve (10), the third vacuum isolation valve (12), the first steam isolation valve (13), the steam delivery unit (18) and the cooling water delivery unit (19) are controlled to be opened, and the second vacuum isolation valve (11) and the third steam isolation valve (15) are closed; at this time, the fuel gas flows from the gas collecting chamber (1) to the vacuum suction pipeline (2), the first vacuum jet pump (3), the first condenser (8), the second vacuum jet pump (4), the second condenser (9), the third vacuum jet pump (5) and the third variable pump (6); at the same time, the motive steam is transported through the steam delivery The unit (18) is respectively transported to the primary vacuum jet pump (3), the secondary vacuum jet pump (4), the tertiary vacuum jet pump (5) and the tertiary variable pump (6); the cooling water is transported to the primary condenser (8) and the secondary condenser (9) through the cooling water transport unit (19) to cool the condensable part of the mixed gas of the fuel gas and the steam; the primary vacuum jet pump (3), the secondary vacuum jet pump (4), the tertiary vacuum jet pump (5) and the tertiary variable pump (6) accelerate the power steam to a supersonic state, and draw the cooled steam to complete the injection of the engine fuel gas; The switching of the third-level working mode to the fourth-level working mode is specifically as follows: The first vacuum isolation valve (10), the third vacuum isolation valve (12) and the first steam isolation valve (13) are controlled to be closed, and the second vacuum isolation valve (11) and the third steam isolation valve (15) are controlled to be opened; at this time, the fuel gas flows from the gas collecting chamber (1) to the fourth-stage vacuum jet pump (7), the first-stage vacuum jet pump (3), the first-stage condenser (8), the second-stage vacuum jet pump (4), the second-stage condenser (9), and the third-stage vacuum jet pump (5); at the same time, the motive steam is respectively transported to the first-stage vacuum jet pump (3), the second-stage vacuum jet pump (4), the third-stage vacuum jet pump (5) and the fourth-stage vacuum jet pump (7) through the steam transport unit (18); the cooling water is transported to the first-stage condenser (8) and the second-stage condenser (9) through the cooling water transport unit (19) to cool the condensable part of the mixed gas of the fuel gas and the steam; the first-stage vacuum jet pump (3), the second-stage vacuum jet pump (4), the third-stage vacuum jet pump (5) and the fourth-stage vacuum jet pump (7) accelerate the motive steam to a supersonic state, and suck the cooled steam to complete the injection of the engine fuel gas.

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