A double-side air intake volute for an aviation environmental control ram refrigeration turbine

Abstract

The present invention discloses a double-sided air intake volute for an aviation environmental control ramjet refrigeration turbine, comprising a power turbine arranged inside the shell, a nozzle ring arranged on the power turbine, a volute inlet arranged on the shell, and an annular flow channel arranged inside the shell; the annular flow channel comprises two volute flow channel 1 and volute flow channel 2, and the two are symmetrically arranged on both sides of the nozzle ring; the fluid medium transported through the volute inlet will decelerate after entering the large cross-section flow channel formed by the volute flow channel 1 and the volute flow channel 2, thereby achieving a pressure diffusion effect, thereby forming a low flow rate and high static pressure area at the nozzle ring inlet. The present invention hollows out the internal solid support structure of the ramjet turbine to form double volute flow channels on both sides of the nozzle under the condition of satisfying the structural strength, increases the cross-sectional area of ​​the volute flow channel without increasing the volume of the ramjet turbine, and achieves the purpose of decelerating and diffusing the high-speed ramjet air, which is more conducive to the efficient operation of the ramjet turbine, and can also reduce the weight of the ramjet turbine and the load on the carrier aircraft.

Description

Technical Field

[0001] The present invention relates to the technical field of turbo expanders and air refrigeration, and in particular to a double-sided air intake volute for an aviation environmental control ramjet refrigeration turbine. Background Art

[0002] Military aircraft generally improve their tactical performance by adding pods, expanding their onboard functions and performance in the fields of electronic countermeasures, reconnaissance, navigation and guidance. In order to ensure the reliable operation of the pod electronic equipment, an independent environmental control system must be installed in the pod, and the pod environmental control system usually uses a ramjet turbine as the core cooling solution.

[0003] The ram air generated by the flight of the aircraft enters the turbine through the pod inlet, drives the refrigeration turbine to rotate at high speed, realizes the enthalpy drop of the working fluid, and transmits the energy released by the expansion of the working fluid to the compressor at the other end in the form of mechanical work through the main shaft. The low-pressure air in the cabin is compressed and turbocharged and then discharged outside the cabin to form an open cycle. At the same time, the suction effect of the compressor can reduce the pressure in the cabin and improve the expansion ratio and refrigeration performance of the refrigeration turbine. Since the ram refrigeration turbine uses ram air as a power source, it does not need to consume electricity, and the refrigeration capacity increases with the increase of Mach number, which can overcome the effect of the increase of aerodynamic heat load with the increase of Mach number within a certain range. In order to better meet the increasing requirements of electronic pods for cooling capacity, a ram turbine refrigeration solution driven by a power turbine has emerged. Part of the ram air is expanded and output through the additional power turbine, which can increase the air intake of the refrigeration turbine and make the system work under the design conditions as much as possible, thereby obtaining a larger turbine temperature drop and cooling capacity. It can solve the problems of large design size of the typical ram turbine wheel diameter and low working efficiency under non-design conditions. It is the main environmental control cooling method adopted by mainstream pods at home and abroad.

[0004] like Figure 1 As shown in the figure, the refrigeration turbine and the power turbine are collectively referred to as the working wheel, which can use the speed change of the ram air flowing in its own flow channel to convert energy, and the working wheel shaft outputs external work, thereby reducing the internal energy and temperature of the turbine outlet air to achieve refrigeration. The flow section of the working wheel can be divided into four parts according to the order of airflow, namely, the volute, the nozzle, the impeller and the outlet diffuser. The ram air introduced into the pod inlet is distributed to the nozzle ring inlet after being guided by the volute. Generally speaking, the gas flowing in the volute has no energy conversion except flow loss. The airflow guided by the volute is accelerated after passing through the contraction channel or the zoom-type channel inside the nozzle, and realizes initial expansion in the nozzle. After obtaining partial temperature drop and a large speed, it drives the impeller to rotate at high speed, outputs shaft work to the outside, and continues to expand and cool in it, further reducing the specific enthalpy and temperature.

[0005] Different from the ground application scenario, the ramjet refrigeration turbine driven by aviation ram air has the characteristics of large flow, high inlet air velocity, low total pressure, high temperature, and low density. In order to ensure that the ramjet turbine installed inside the pod has sufficient air intake, the diameter of the pod inlet pipe will be larger than the diameter required for normal turbine intake to compensate for the flow loss of high-speed airflow (usually above Mach number 0.65) in the inlet duct. When high-speed ramjet air enters the nozzle without expansion and deceleration, flow field turbulence, increased eddy loss, insufficient expansion in the nozzle and other factors that are not conducive to the operation of the ramjet turbine will occur, affecting the turbine refrigeration efficiency. In the case of subsonic speed, the use of a gradually expanding inlet duct to expand the airflow before it enters the turbine requires an increase in the cross-sectional area and volume of the inlet duct, which occupies a large amount of equipment space in the cabin and is not conducive to the operation of aviation airborne equipment. Therefore, the cross-sectional area of ​​the volute can be increased to use the space inside the volute to achieve deceleration and expansion buffering of high-speed airflow. However, for aviation ramjet refrigeration turbines driven by power turbines, since the power turbine is located in the middle of the turbine casing and is affected by the middle bearing, main shaft, supporting structure, etc., increasing the cross-sectional area of ​​the single-sided air intake volute will increase the volume of the turbine and will also occupy space for equipment in the cabin, which is contrary to the strict requirements on the volume and weight of cabin equipment under aviation airborne conditions. Summary of the invention

[0006] The double-sided air intake volute for an aviation environmental control ramjet refrigeration turbine proposed in the present invention can solve the volume occupation problem caused by using an inlet diffuser to expand the air, and the problem of increased turbine volume caused by increasing the cross-sectional area of ​​a single-sided volute for expansion, while at the same time effectively utilizing the internal space of the ramjet turbine.

[0007] To achieve the above object, the present invention adopts the following technical solutions:

[0008] A double-side air intake volute for an aviation environmental control ram refrigeration turbine comprises a housing, a power turbine is arranged inside the housing, a nozzle ring is arranged correspondingly at the inlet of the power turbine, and the nozzle ring is used to convert the total pressure of a fluid working medium into a speed to provide a driving torque for the power turbine;

[0009] The shell is provided with a volute inlet, and an annular flow channel is provided inside the shell;

[0010] An airflow outlet pipe is arranged on the shell, and the airflow flows out through the airflow outlet pipe;

[0011] The annular flow channel includes two volute flow channel 1 and volute flow channel 2, which are symmetrically arranged on both sides of the nozzle ring;

[0012] The volute inlet is connected to the air inlet and is used to transport fluid. The fluid transported through the volute inlet will decelerate after entering the large-section flow channel formed by the volute flow channels on both sides of the volute flow channel 1 and volute flow channel 2, thereby achieving a pressure diffusion effect, thereby forming a low flow rate and high static pressure area at the nozzle ring inlet.

[0013] Furthermore, the volute flow channel 2 is the original volute flow channel of the power turbine, and the volute flow channel 2 is manufactured into a uniform cross-section form by turning.

[0014] Furthermore, the volute flow channel 1 is a volute flow channel additionally provided by utilizing the internal support structure of the ramjet turbine, and the volute flow channel 1 is manufactured into a uniform cross-section form by turning.

[0015] Furthermore, the nozzle ring is a nozzle with a rectangular cross-section manufactured by milling and is installed in the middle of the volute flow passages on both sides.

[0016] Furthermore, the power turbine is a power turbine formed by milling, is supported and rotated by a high-speed bearing and a rotating shaft, and is installed at the axial position of the nozzle ring, the volute flow channel 1, and the volute flow channel 2.

[0017] Furthermore, the nozzle ring and the volute flow channel are processed as one piece.

[0018] Furthermore, the volute flow passage 1 is fastened to the shell by screws.

[0019] Furthermore, the volute flow passage 2 is welded to the shell at a joint.

[0020] The present invention proposes a double-sided air intake volute with a pressure diffusion function, and uses the support structure space inside the aviation ramjet turbine to set the power turbine volute flow channel, which is used in conjunction with the original volute flow channel to increase the cross-sectional area of ​​the volute flow channel, thereby playing a role in decelerating and diffusing the aviation ramjet air at the turbine inlet. At the same time, the weight can be reduced without changing the volume of the ramjet turbine. Specifically, the space on both sides of the nozzle inside the casing is used as the volute flow channel to increase the flow cross-sectional area before the nozzle inlet. Under a nearly adiabatic state, the gas flow is decelerated and diffused by increasing the cross-sectional area and volume, so that it is close to a stagnant state, effectively reducing the flow loss of the turbine flow part, and the expansion in the nozzle is closer to an ideal state, which can greatly improve the refrigeration efficiency. At the same time, the solid part inside the turbine is hollowed out as a flow channel without affecting the structural strength, which can reduce the weight of the body and is more friendly to aviation applications.

[0021] The present invention utilizes the topological optimization method to set flow channels in the space on both sides of the nozzle inside the ram turbine casing on the basis of ensuring the structural strength and processability of the turbine, thereby increasing the cross-sectional area and internal volume of the volute, decelerating and expanding the high-speed ramjet airflow, so as to achieve uniform air intake of the nozzle under the condition of relatively small pressure loss, reduce friction loss and eddy loss, and improve the working efficiency of the turbine.

[0022] The present invention designs and processes the solid structural parts on both sides of the power wheel nozzle into volute flow channels inside the aviation ramjet driven by the power turbine, that is, double-sided air intake volutes, both of which are in the form of upper volutes and are located on both sides of the nozzle ring. The volute flow channel is a relatively sealed annular space connecting the inlet pipe and the nozzle. The cross-sectional area of ​​the volute flow channel is maximized through strength verification under the condition of ensuring structural strength. After the ram air enters the turbine through the air intake duct, it first enters the volute flow channels on both sides of the nozzle. During the circumferential flow of the airflow along the volute flow channel, it continuously flows radially from both sides of the nozzle inlet to the inside of the nozzle. The introduction of the double-sided volute greatly increases the cross-sectional area of ​​the flow channel, so that the airflow velocity at the same flow rate in the volute is significantly reduced, which can usually be controlled within 12m / s. There is no need to adopt the variable cross-section design of the traditional volute to meet the axisymmetric exhaust and ensure that the circumferential airflow velocity (usually 15-20m / s) of the volute outlet remains unchanged. Therefore, the double-sided volute flow channel can be in the form of equal cross-section to reduce the manufacturing difficulty.

[0023] It can be seen from the above technical scheme that the double-sided air inlet volute for the aviation environmental control ramjet refrigeration turbine of the present invention relates to a type of turbine expander volute, which belongs to the field of turbine expanders and air refrigeration. Specifically, it is a flow channel that uses the space on both sides of the nozzle for flow guidance and pressure expansion buffering. It can be used in a turbine expander driven by incoming air with a large volume, high flow rate and low static pressure. It has high applicability in the field of aviation environmental control air conditioning where the requirements on the weight load, volume load and other aspects of the refrigeration turbine are relatively stringent. The ram refrigeration turbine is driven by the ram air generated by the flight of the aircraft. The inlet airflow has the characteristics of low static pressure, high flow rate and high dynamic pressure. In order to reduce the flow loss generated in the volute before the high-speed airflow enters the nozzle, ensure that the airflow can expand and accelerate smoothly after entering the nozzle evenly, and prevent the occurrence of vortexes that affect the refrigeration efficiency, and also to reduce the space occupation in the cabin caused by the use of a gradually expanding diffuser to complete the conversion of airflow dynamic pressure to static pressure when the aircraft is flying at subsonic speed, the present invention proposes a volute form with air intake, diffusion and flow guidance on both sides of the nozzle, which can effectively utilize the internal space of the ram turbine for high-speed fluid diversion, and while reducing the airflow velocity in the volute, the high-speed ram air is expanded in the large-section volute, which can effectively increase the static pressure at the nozzle inlet, reduce the flow velocity, reduce vortexes and friction losses, thereby improving the refrigeration efficiency of the ram turbine, and can meet the stringent requirements on the performance and space occupation of refrigeration equipment under aviation airborne conditions.

[0024] In summary, the present invention utilizes the method of structural topology optimization to hollow out the internal solid support structure of the ramjet turbine while satisfying the structural strength to form double volute flow passages on both sides of the nozzle, thereby increasing the cross-sectional area of ​​the volute flow passage without increasing the volume of the ramjet turbine, thereby achieving the purpose of decelerating and expanding the high-speed ramjet air, which is more conducive to the efficient operation of the ramjet turbine and can also reduce the weight of the ramjet turbine and the load on the carrier aircraft. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a ram turbine refrigeration solution driven by a power turbine;

[0026] Figure 2 It is a structural schematic diagram of the volute of the present invention;

[0027] Figure 3 Schematic diagram of the airflow direction of the volute of the present invention. DETAILED DESCRIPTION

[0028] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments.

[0029] The double-side air intake volute for the aviation environmental control ramjet refrigeration turbine described in this embodiment is as follows: Figure 2 As shown, 1 is a rectangular cross-section nozzle ring of a power turbine, which is used to convert the total pressure of the fluid working medium into speed and provide sufficient driving torque for the power turbine 5; 2 is the inlet of the power turbine volute, which is connected to the air inlet and is used to transport the fluid working medium to the nozzle and the power turbine. 3 is an annular volute flow channel with equal cross-section on one side of the nozzle, which is used to evenly distribute the internal airflow to the inlet of the nozzle ring; 4 is an annular volute flow channel with equal cross-section on the other side of the nozzle; the high-flow rate and low-static pressure fluid working medium transported through the volute inlet 2 will be fully decelerated after entering the large-section flow channel formed by the volute flow channel 1 3 and the volute flow channel 2 4 on both sides of the volute flow channel, and the pressure expansion effect is achieved under the condition of near-insulation, thereby forming a low-flow rate and high-static pressure area at the nozzle inlet. 5 is a power turbine, and 1 is a high-speed rotation driven by the high-speed airflow at the nozzle outlet, and the shaft work is output to the outside, so that the specific enthalpy and temperature of the fluid working medium are reduced, and the refrigeration function is realized. 6 is the casing of the turbine, which provides sealing and support for the internal flow channel and components.

[0030] Figure 2 Reference numeral 4 is the original volute flow passage of the power turbine, which is made into a uniform cross-section form by turning processing. Reference numeral 3 is the volute flow passage optimized by utilizing the internal supporting structure of the ramjet turbine, which is also made into a uniform cross-section form by turning processing. The annular flow passage does not have to be uniform in cross-section. In order to comply with the law of the plane free vortex, the conventional flow passage must be made into a variable cross-section. However, the implementation of a variable cross-section is difficult and costly. After the double-sided volute is adopted in the present invention, the cross-sectional area of ​​the flow passage is increased, the airflow velocity is reduced, and it is more cost-effective and easy to implement to make it into a uniform cross-section.

[0031] Figure 2 1 is a rectangular cross-section nozzle made by milling, installed in the middle of the volute flow passage on both sides. 5 is a power turbine formed by milling, which is supported by high-speed bearings and rotating shafts and installed on Figure 2The axes of the nozzle ring 1, volute flow channel 1 3, and volute flow channel 2 4 rotate at high speed under the impetus of the high-speed airflow that has been steadily accelerated by the nozzle ring 1, thereby achieving enthalpy drop and temperature drop of the working fluid.

[0032] Specifically, the nozzle ring 1 and the volute flow channel 3 are integrally processed, the volute flow channel 3 is fastened to the housing 6 by screws 7, the volute flow channel 4 is welded to the housing 6 at the joint, and the airflow flows out through the airflow outlet pipe 8.

[0033] The airflow direction of the volute of the present invention is as follows: Figure 3 As shown, the specific principles of the present invention are analyzed and explained below:

[0034] Figure 1 The total temperature of the ram air at the inlet of the ram turbine refrigeration solution can be expressed as:

[0035] t t =t s (1+Ma 2 / 5)

[0036] The total pressure can be expressed as:

[0037]

[0038] The local speed of sound is:

[0039]

[0040] When the aircraft flies at a Mach number of 0.65 at an altitude of 300 meters, under the conditions of an ambient temperature of 38°C and an atmospheric pressure of 99kPa, the total temperature of the ram air is 64°C, the total pressure is 129kPa, the local speed of sound is 340m / s, and the air velocity corresponding to the Mach number of 0.65 is 221m / s. From fluid mechanics, it is known that the drag loss is proportional to the square of the flow velocity. When a high-speed airflow with a speed of 221m / s flows in the flow channel before entering the nozzle, it will cause great drag loss, and the total pressure loss is as high as 10%, which has a greater impact on the operation of the ramjet turbine with a lower inlet total pressure. Therefore, this part of the ram air must be fully decelerated and expanded before entering the nozzle and turbine.

[0041] The relationship between air flow cross-sectional velocity and flow rate can be expressed as:

[0042] q=ρvA

[0043] When the ramjet turbine is designed to have a gas volume of 400 kg / h, the cross-sectional area is 0.004 m2 and the air velocity at the volute inlet is 21 m / s. Figure 2The air flow velocity at the inlets on both sides of the double-sided air intake volute is 10.5m / s, and as the air flow flows along the volute and continuously enters the nozzle, the flow at the far end of the volute inlet will gradually decrease, causing the air flow velocity in the volute to further decrease, approaching a stagnant state. Since the gas flow in the volute can be regarded as an adiabatic process, no energy conversion occurs. Therefore, the total pressure of the air flow inside the volute remains unchanged, the dynamic pressure decreases, and the static pressure increases, achieving the goal of deceleration and pressure expansion, which is very necessary for the above-mentioned operating conditions.

[0044] As can be seen from the above, the double-sided air intake volute for an aviation ramjet refrigeration turbine with a pressure diffusion function of the present invention is to use the support structure space inside the aviation ramjet turbine to set the power turbine volute flow channel, and to cooperate with the original volute flow channel to increase the cross-sectional area of ​​the volute flow channel, so as to play a role in decelerating and diffusing the aviation ramjet air at the turbine inlet. At the same time, the weight can be reduced under the condition that the volume of the ramjet turbine remains unchanged. The double-sided air intake volute is in the form of an upper volute, located on both sides of the nozzle ring.

[0045] The double-sided air intake volute with a pressure diffusion function for an aviation ram refrigeration turbine of the present invention is used for an airborne ring-controlled cold turbine that uses aviation ram air as a power source and a refrigerant. It can decelerate and diffuse large volume, high velocity, and low static pressure aviation ram air by increasing the internal flow cross-sectional area of ​​the volute, thereby reducing flow losses and improving refrigeration efficiency. At the same time, since the air flow velocity after the diffusion is relatively low and close to a stagnant state, it is not necessary to meet the axisymmetric exhaust requirements of the traditional volute with a variable cross-section, and a volute with a uniform cross-section can be used to reduce the difficulty of volute processing. The double-sided air intake volute is located inside the ram refrigeration turbine, on both sides of the power turbine nozzle, and can effectively utilize the internal support structure space of the turbine without increasing the overall volume. At the same time, it can reduce the weight of the fuselage, which is more friendly to aviation airborne applications.

[0046] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A double-sided air intake volute for an aviation environmentally controlled ram refrigeration turbine, comprising a housing (6), a power turbine (5) being arranged inside the housing (6), a nozzle ring (1) being arranged correspondingly on the power turbine (5), the nozzle ring (1) being used to convert the total pressure of a fluid working medium into a velocity, thereby providing a driving torque for the power turbine (5); The housing (6) is provided with a volute inlet (2), and an annular flow channel is provided inside the housing (6); An airflow outlet pipe (8) is provided on the shell (6), and the airflow flows out through the airflow outlet pipe (8); Features: The annular flow channel comprises two volute flow channel 1 (3) and volute flow channel 2 (4), the two volute flow channel 1 and volute flow channel 2 (4) being symmetrically arranged on both sides of the nozzle ring (1); The volute inlet (2) is connected to the air inlet and is used to convey the fluid. The fluid conveyed through the volute inlet (2) is decelerated after entering the large cross-section flow channel formed by the volute flow channels on both sides of the volute flow channel 1 (3) and the volute flow channel 2 (4), thereby achieving a pressure diffusion effect, thereby forming a low flow rate and high static pressure area at the inlet of the nozzle ring (1); The volute flow channel one (3) is a volute flow channel additionally provided by utilizing the internal support structure of the ramjet turbine, and the volute flow channel one (3) is manufactured into a uniform cross-section form by turning; The power turbine (5) is a power turbine formed by milling, is supported and rotated by a high-speed bearing and a rotating shaft, and is installed at the axis position of the nozzle ring (1), the volute flow channel 1 (3), and the volute flow channel 2 (4).

2. The double-side air intake volute for the aviation environmental control ram refrigeration turbine according to claim 1 is characterized in that: The second volute flow channel (4) is the original volute flow channel of the power turbine (5), and the second volute flow channel (4) is manufactured into a uniform cross-section form by turning.

3. The double-side air intake volute for the aviation environmental control ram refrigeration turbine according to claim 1, characterized in that: The nozzle ring (1) is a nozzle with a rectangular cross section manufactured by milling and is installed in the middle of the volute flow passages on both sides.

4. The double-side air intake volute for the aviation environmental control ram refrigeration turbine according to claim 1, characterized in that: The nozzle ring (1) and the volute flow channel (3) are integrally machined.

5. The double-side air intake volute for the aviation environmental control ram refrigeration turbine according to claim 1, characterized in that: The volute flow passage 1 (3) is fastened to the housing (6) by means of screws (7).

6. The double-side air intake volute for the aviation environmental control ram refrigeration turbine according to claim 1, characterized in that: The volute flow passage 2 (4) is connected to the casing (6) by welding at the joint.

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