Design method of injection inflation system

Abstract

The invention discloses an injection inflation system design method which comprises the following steps: determining parameters of a high-pressure gas storage device and the configuration of an injection device according to the target pressure and volume of a gas collection device, so that the system can entrain the atmosphere by utilizing the turbulent diffusion effect of jet flow in a relatively stable flow stage, and the jet flow flows into the gas collection device after completing kinetic energy exchange; enabling the gas collection device to approach the target pressure; and when the flow starts to drop, the injection device stops working, and residual gas of the high-pressure gas storage device continuously flows into the gas collection device under the action of pressure difference, so that the gas collection device reaches target pressure. According to the design method, the design target and the target control parameters are provided, the improvement of the inflation efficiency and the reduction of the system volume can be guided, the design is prevented from being changed by repeated tests, and the waste of time and financial resources is reduced.

Description

Technical Field

[0001] The invention relates to jet inflation, and in particular to a design method for a jet inflation system. Background Art

[0002] Regarding the ejection inflation system, Figure 1 As shown, it usually includes a high-pressure gas storage device, a pressure reducing valve, an ejection device and a nozzle. The nozzle is arranged inside the ejection device. The high-pressure gas (liquid) in the high-pressure gas storage device flows into the ejection device after being reduced in pressure by the pressure reducing valve, and forms a high-speed jet after passing through the nozzle. Under the turbulent diffusion action of the jet, the surrounding atmosphere is entrained and kinetic energy is exchanged with the atmosphere to form a mixed airflow with a certain speed, which finally flows into the gas collecting device, thereby quickly inflating the gas collecting device.

[0003] The jet inflation system is generally used in emergency situations where rapid inflation is required, such as for inflating airplane slides. Therefore, it is necessary to ensure inflation efficiency and volume without occupying space. However, the current jet inflation system has no clear design ideas, and cannot guide the improvement of inflation efficiency and the reduction of system volume. Repeated experiments and design changes are required to meet the requirements, wasting a lot of time and financial resources. Summary of the invention

[0004] The purpose of the present invention is to provide a method for designing an ejection inflation system, which proposes design objectives and target control parameters, can guide the improvement of inflation efficiency and the reduction of system volume, avoids repeated experiments to change the design, and reduces the waste of time and financial resources.

[0005] The technical solution adopted by the present invention is:

[0006] A method for designing an ejector inflation system determines the parameters of a high-pressure gas storage device and the configuration of an ejector device according to the target pressure and volume of a gas collecting device, so that the system: in a relatively stable flow stage, uses the turbulent diffusion effect of the jet to entrain the atmosphere, and flows into the gas collecting device after completing the kinetic energy exchange, so that the gas collecting device approaches the target pressure; when the flow begins to decrease, the ejector device stops working, and the remaining gas in the high-pressure gas storage device continues to flow into the gas collecting device under the action of the pressure difference, so that the gas collecting device reaches the target pressure.

[0007] Furthermore, the volume V of the gas collecting device is known. m , target pressure P at a certain temperature T m , Target pressure P m When determining the parameters of the high-pressure gas storage device and the configuration of the ejection device: First, determine the ejection pressure P in The design value and the corresponding jet mass flow rate q, and then determine the pressure reducing valve outlet pressure P d The design value of the high-pressure gas storage device pressure value P corresponding to the exit timing of the relatively stable flow stageg As well as the working fluid mixture density, the average ejection ratio in the relatively stable flow stage The design value of the ideal mass of the working fluid entering the gas collecting device during the flow rate decline phase, the design value of the ideal mass of the working fluid participating in the induced diffusion and kinetic energy exchange, the design value of the duration t of the relatively stable flow phase, and the design value of the pressure P0 of the high-pressure gas storage device; then, first determine whether the design value of the duration t of the relatively stable flow phase meets the use requirements, and adjust the induced pressure P in The design value or configuration of the ejector device is adjusted to meet the use requirements, and then it is determined whether the design value of the pressure P0 of the high-pressure gas storage device meets the use requirements, and the working fluid composition and mass ratio are adjusted to meet the use requirements; finally, the average ejection ratio is adjusted according to the inflation test results. Get the value.

[0008] Furthermore, when determining the parameters of the high-pressure gas storage device and the configuration of the ejector device, the following steps are adopted:

[0009] Step 1: Specify the working fluid composition and mass proportion λ1, λ2…λ in the high-pressure gas storage device i , for a certain temperature T of the ejector and different ejection pressures P in , different outlet pressure P out CFD simulation calculations were performed under the conditions to obtain the changing trends of the jet mass flow rate q, the suction gas mass flow rate Q, and the ejection ratio δ, and the outlet pressure P when the ejection ratio δ approaches 0. out ’ Less than and close to the target pressure P m , thus determining the injection pressure P in The design value of and the corresponding jet mass flow rate q;

[0010] Step 2: Calculate the pressure reducing valve outlet pressure P d Design value

[0011] P d =ηP in (1)

[0012] Where, η is the pressure drop coefficient of the pipeline between the pressure reducing valve and the ejector;

[0013] Step 3: Calculate the pressure value P of the high-pressure gas storage device corresponding to the exit timing of the relatively stable flow stage g

[0014] P g ≈P d / σ(2)

[0015] Where σ is the critical pressure ratio of the mixed working fluid in the high-pressure gas storage device, and the working fluid mixed density is ρ(λ1, λ2…λ i , Pg );

[0016] Step 4: Determine the average ejection ratio during the relatively stable flow phase is the injection pressure P in Under the design value, the outlet pressure P out 0.5~0.7 times P out ’ The corresponding ejection ratio when

[0017] Step 5: Calculate the ideal mass of the working fluid entering the gas collecting device during the flow rate reduction phase m1, m2…m i Design value

[0018] m1, m2…m i =[λ1,λ2…λ i ]·ρ(λ1, λ2…λ i , P g )V g (3)

[0019] Where V g is the volume of the high pressure gas storage device;

[0021] Step 6: Calculate the ideal mass m1′, m2′…m of the working fluid involved in the injection diffusion and kinetic energy exchange i Design value of ′

[0022]

[0024] In the formula, M1, M2…M i is the molar mass of each working fluid in the high-pressure gas storage device, M0 is the molar mass of the entrained ambient atmosphere, is the average ejection ratio, R is the gas constant;

[0025] Step 7: Calculate the design value of the duration t of the relatively stable flow phase

[0027] t=(m1′+m2′+…+m i ′) / q (5)

[0028] Step 8: Calculate the design value of the pressure P0 of the high-pressure gas storage device

[0030] P0=P(λ1、λ2…λ i ,(m1+m2+…+m i +m1′+m2′+…+m i ′) / V g ) (6)

[0031] The design value of the pressure P0 of the high-pressure gas storage device is determined by the mass proportion of the working fluid λ1, λ2…λ i and total density;

[0032] Step 9: Determine whether the design value of the duration t of the relatively stable flow phase meets the use requirements. If not, adjust the injection pressure P in or the configuration of the ejector device, and repeat steps 1 to 8 until the design value of the duration t of the relatively stable flow phase meets the use requirements;

[0033] Step 10: Determine whether the design value of the pressure P0 of the high-pressure gas storage device meets the use requirements. If not, adjust the working fluid composition and mass proportion λ1, λ2…λ i , and repeat steps 1 to 8 until the design value of the pressure P0 of the high-pressure gas storage device meets the use requirements;

[0034] Step 11: Adjust the average ejection ratio based on the inflation test results Get the value.

[0035] The beneficial effects of the present invention are:

[0036] This design method proposes design goals and target control parameters, which can guide the improvement of inflation efficiency and the reduction of system volume, avoid repeated experiments to change the design, and reduce the waste of time and financial resources. When used to inflate aircraft slides, it improves inflation efficiency and reduces system volume. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 It is a structural diagram of the ejection inflation system.

[0038] Figure 2 A schematic diagram of CFD simulation calculation of an ejector device in an embodiment of the present invention.

[0039] Figure 3 A schematic diagram of the value of the average ejection ratio in an embodiment of the present invention.

[0040] In the figure: 1-high pressure gas storage device; 2-pressure reducing valve; 3-injection device; 4-gas collecting device; 5-nozzle. DETAILED DESCRIPTION

[0041] The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0042] The present application provides a method for designing an ejection inflation system, wherein the ejection inflation system adopts a conventional structure, such as Figure 1As shown, it includes a high-pressure gas storage device 1, a pressure reducing valve 2, an ejector device 3 and a nozzle 5. The nozzle 5 is arranged inside the ejector device 3. The high-pressure gas (liquid) in the high-pressure gas storage device 1 flows into the ejector device 3 after being reduced in pressure by the pressure reducing valve 2, and forms a high-speed jet after passing through the nozzle 5. Under the turbulent diffusion effect of the jet, the surrounding atmosphere is entrained, and kinetic energy is exchanged with the atmosphere to form a mixed airflow with a certain speed, and finally flows into the gas collecting device 4, so as to quickly inflate the gas collecting device 4. The principle of this design method is to determine the parameters of the high-pressure gas storage device 1 and the configuration of the ejector device 3 according to the target pressure and volume of the gas collecting device 4, so that the system: in the relatively stable flow stage, the turbulent diffusion effect of the jet is used to entrain the atmosphere, and after the kinetic energy exchange is completed, it flows into the gas collecting device 4, so that the gas collecting device 4 is close to the target pressure; when the flow begins to decrease, the ejector device 3 stops working, and the remaining gas in the high-pressure gas storage device 1 continues to flow into the gas collecting device 4 under the action of the pressure difference, so that the gas collecting device 4 reaches the target pressure.

[0043] In this embodiment, the following steps are used to determine the parameters of the high-pressure gas storage device 1 and the configuration of the ejection device 3:

[0044] Step 1: Specify the working fluid composition and mass proportion λ1, λ2…λ in the high-pressure gas storage device 1 i , for a certain temperature T of the ejector 3 and different ejection pressures (inlet pressures) P in , different outlet pressure P out CFD simulation calculations are performed under the following conditions: Figure 2 As shown in the figure, the variation trend of the jet mass flow rate q, the suction gas mass flow rate Q, and the ejection ratio δ is obtained, and the outlet pressure P when the ejection ratio δ approaches 0 is out ’ Less than and close to the target pressure P m , thus determining the injection pressure P in The design value of and the corresponding jet mass flow rate q;

[0045] Step 2: Calculate the outlet pressure P of pressure reducing valve 2 d Design value

[0046] P d =ηP in (1)

[0047] Wherein, η is the pressure drop coefficient of the pipeline between the pressure reducing valve 2 and the ejector device 3;

[0048] Step 3: Calculate the pressure value P of the high-pressure gas storage device 1 corresponding to the exit timing of the relatively stable flow stage g

[0049] P g ≈P d / σ(2)

[0050] Where σ is the critical pressure ratio of the mixed working fluid in the high-pressure gas storage device 1, and the working fluid mixed density is ρ(λ1, λ2…λ i , P g );

[0051] Step 4: Determine the average ejection ratio during the relatively stable flow phase is the injection pressure P in Under the design value, Figure 3 As shown, the outlet pressure P out 0.5~0.7 times P out ’ The corresponding ejection ratio when

[0052] Step 5: Calculate the ideal mass m1, m2…m of the working fluid entering the gas collecting device 4 during the flow rate reduction stage i Design value

[0053] m1, m2…m i =[λ1,λ2…λ i ]·ρ(λ1, λ2…λ i , P g )V g (3)

[0054] Where V g is the volume of the high pressure gas storage device 1;

[0056] Step 6: Calculate the ideal mass m1′, m2′…m of the working fluid involved in the injection diffusion and kinetic energy exchange i Design value of ′

[0057]

[0059] In the formula, M1, M2…M i is the molar mass of each working fluid in the high-pressure gas storage device 1, M0 is the molar mass of the entrained ambient atmosphere, is the average ejection ratio, R is the gas constant;

[0060] Step 7: Calculate the design value of the duration t of the relatively stable flow phase

[0062] t=(m1′+m2′+…+m i ′) / q (5)

[0063] Step 8: Calculate the design value of the pressure P0 of the high-pressure gas storage device 1

[0065] P0=P(λ1、λ2…λ i,(m1+m2+…+m i +m1′+m2′+…+m i ′) / V g ) (6)

[0066] The design value of the pressure P0 of the high-pressure gas storage device 1 is determined by the mass proportions of the working fluid λ1, λ2…λ i and total density;

[0067] Step 9: Determine whether the design value of the duration t of the relatively stable flow phase meets the use requirements. If not, adjust the injection pressure P in or the configuration of the ejector 3, and repeat steps 1 to 8 until the design value of the duration t of the relatively stable phase of the flow rate meets the use requirements;

[0068] Step 10: Determine whether the design value of the pressure P0 of the high-pressure gas storage device 1 meets the use requirements. If not, adjust the working fluid composition and mass proportion λ1, λ2…λ i , and repeat steps 1 to 8 until the design value of the pressure P0 of the high-pressure gas storage device 1 meets the use requirements;

[0069] Step 11: Adjust the average ejection ratio based on the inflation test results Get the value.

[0070] This design method proposes design goals and target control parameters, which can guide the improvement of inflation efficiency and the reduction of system volume, avoid repeated experiments to change the design, and reduce the waste of time and financial resources. When used to inflate aircraft slides, it improves inflation efficiency and reduces system volume.

[0071] The embodiments described above are part of the embodiments of the present application, rather than all of the embodiments. The detailed description of the embodiments of the present application is not intended to limit the scope of the present application for protection, but merely represents the selected embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present application.

Claims

1. A method for designing an ejection inflation system, characterized in that: The parameters of the high-pressure gas storage device and the configuration of the ejector device are determined according to the target pressure and volume of the gas collecting device, so that the system: in the relatively stable flow stage, the turbulent diffusion effect of the jet is used to draw in the atmosphere, and after completing the kinetic energy exchange, it flows into the gas collecting device, so that the gas collecting device approaches the target pressure; when the flow begins to decrease, the ejector device stops working, and the remaining gas in the high-pressure gas storage device continues to flow into the gas collecting device under the action of the pressure difference, so that the gas collecting device reaches the target pressure.

2. The method for designing an ejection inflation system according to claim 1, characterized in that: The volume V of the gas collecting device is known m , target pressure P at a certain temperature T m , Target pressure P m When determining the parameters of the high-pressure gas storage device and the configuration of the ejection device: First, determine the ejection pressure P in The design value and the corresponding jet mass flow rate q, and then determine the pressure reducing valve outlet pressure P d The design value, the high pressure corresponding to the exit timing of the relatively stable flow stage --- Gas storage device pressure value P g As well as the working fluid mixture density, the average ejection ratio δ in the relatively stable flow stage, the design value of the ideal mass of the working fluid entering the gas collecting device in the flow decreasing stage, the design value of the ideal mass of the working fluid participating in the ejection diffusion and kinetic energy exchange, the design value of the duration t in the relatively stable flow stage, and the design value of the pressure P0 of the high-pressure gas storage device; then, first determine whether the design value of the duration t in the relatively stable flow stage meets the use requirements, and adjust the ejection pressure P in The design value or configuration of the ejector device is adjusted to meet the use requirements, and then it is determined whether the design value of the pressure P0 of the high-pressure gas storage device meets the use requirements, and the working fluid composition and mass ratio are adjusted to meet the use requirements; finally, the average ejection ratio is adjusted according to the inflation test results. Get the value.

3. The method for designing an ejection inflation system according to claim 2, characterized in that: When determining the parameters of the high-pressure gas storage device and the configuration of the ejector device, the following steps are adopted: Step 1: Specify the working fluid composition and mass proportion λ1, λ2…λ in the high-pressure gas storage device i , for a certain temperature T of the ejector and different ejection pressures P in , different outlet pressure P out CFD simulation calculations were performed under the conditions to obtain the changing trends of the jet mass flow rate q, the suction gas mass flow rate Q, and the ejection ratio δ, and the outlet pressure P when the ejection ratio δ approaches 0. out ’ Less than and close to the target pressure P m , thus determining the injection pressure P in The design value of and the corresponding jet mass flow rate q; Step 2: Calculate the pressure reducing valve outlet pressure P d Design value P d =ηP in (1) Where, η is the pressure drop coefficient of the pipeline between the pressure reducing valve and the ejector; Step 3: Calculate the pressure value P of the high-pressure gas storage device corresponding to the exit timing of the relatively stable flow stage g P g ≈P d / s(2) Where σ is the critical pressure ratio of the mixed working fluid in the high-pressure gas storage device, and the working fluid mixed density is ρ(λ1, λ2…λ i , P g ); Step 4: Determine the average ejection ratio during the relatively stable flow phase is the injection pressure P in Under the design value, the outlet pressure P out 0.5~0.7 times P out ’ The corresponding ejection ratio when Step 5: Calculate the ideal mass of the working fluid entering the gas collecting device during the flow rate reduction phase m1, m2…m i Design value m1、m2…m i =[λ1、λ2…λ i ]·ρ(λ1,λ2…λ i ,P g )V g (3) Where V g is the volume of the high pressure gas storage device; Step 6: Calculate the ideal mass m1, m2…m of the working fluid involved in the injection diffusion and kinetic energy exchange i Design value In the formula, M1, M2…M i is the molar mass of each working fluid in the high-pressure gas storage device, M0 is the molar mass of the entrained ambient atmosphere, is the average ejection ratio, R is the gas constant; Step 7: Calculate the design value of the duration t of the relatively stable flow phase t=(m1+m2+…+m i ) / q (5) Step 8: Calculate the design value of the pressure P0 of the high-pressure gas storage device P0=P(λ1、λ2…λ i ,(m1+m2+…+m i +m1+m2+…+m i ) / V g ) (6) The design value of the pressure P0 of the high-pressure gas storage device is determined by the mass proportion of the working fluid λ1, λ2…λ i and total density; Step 9: Determine whether the design value of the duration t of the relatively stable flow phase meets the use requirements. If not, adjust the injection pressure P in or the configuration of the ejector device, and repeat steps 1 to 8 until the design value of the duration t of the relatively stable flow phase meets the use requirements; Step 10: Determine whether the design value of the pressure P0 of the high-pressure gas storage device meets the use requirements. If not, adjust the working fluid composition and mass proportion λ1, λ2…λ i , and repeat steps 1 to 8 until the design value of the pressure P0 of the high-pressure gas storage device meets the use requirements; Step 11: Adjust the average ejection ratio based on the inflation test results Get the value.

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