Mixing device for simulating high-flow high-low temperature gas in air environment

Abstract

The invention provides a mixing device for simulating high-flow high-low temperature gas in an air environment, which comprises a T-shaped pipeline comprising a first inlet, a second inlet and a converging outlet; the inner space of the T-shaped pipeline is divided into at least two layers of gas flow paths which are independent from each other in the vertical direction by the gas flow layering partition plate; and the high and low temperature partition plate is arranged in the gas flow path and used for blocking gas of the first inlet or the second inlet in the gas flow path, and the first inlet and the second inlet in the gas flow path of two adjacent layers are alternately communicated with the converging outlet through the high and low temperature partition plate. According to the invention, the mixing mechanism of natural flow development of supplied gas incoming flow in a long-distance gas supply pipeline in a traditional scheme is changed from the mixing principle, the heat exchange process is enhanced in space, the mixing efficiency is effectively improved, and the problem of insufficient front-end straight pipe sections caused by space limitation is effectively solved.

Description

Technical Field

[0001] This invention relates to the field of aero-engine technology, and more specifically to a mixing device for simulating high-volume high- and low-temperature gases in the air. Background Technology

[0002] Airborne simulation testing of aircraft engines can simulate parameters such as engine intake air temperature, pressure, and speed during flight, enabling the simulation of the engine's operating state across its entire flight envelope on the ground. During the test, precise and rapid heating and cooling of the engine intake air is required. To achieve rapid switching of engine intake air temperature conditions under different flight conditions, it is often necessary to adjust the flow rates of high and low temperature airflows, ultimately mixing the high and low temperature airflows through a mixer.

[0003] Non-uniform incoming flow fields can cause engine stall or surge. Therefore, in-flight simulation tests have strict requirements for the uniformity of engine inlet temperature. Precise heating and cooling of the supply air is required, and the flow rates of high and low temperature airflows are regulated by the supply air regulating valve. Finally, the high and low temperature airflows are mixed by a mixer to ensure the non-uniformity of engine inlet temperature (≤1%). At the same time, the pressure non-uniformity (≤1%) and turbulence (≤±1%) must also be ensured to minimize the impact of the test stand air supply environment on engine performance parameters and obtain accurate test data during engine testing.

[0004] Meanwhile, the mixers used in air-to-air simulation tests have high requirements for pressure loss and dimensions. For air-to-air simulation tests of civil aircraft engines with flow requirements in the hundreds or even thousands of kilograms per second, excessive pressure loss means high costs for the air supply fans and their operation, and may even make it difficult for the test stand to provide the operating conditions required for engine testing.

[0005] Currently, in the design and construction schemes of air environment simulation test equipment under construction or in use both domestically and internationally, the main structure of the mixing device is a layered baffle type, in which two or more streams of air with different temperatures enter the mixing device and are mixed by splitting the flow.

[0006] The disadvantages of traditional solutions are: 1. The mixing device mainly relies on turbulent diffusion, which requires high and low temperature gases to flow over long distances to achieve uniform temperature mixing, resulting in excessively long pipelines; 2. Traditional mixing devices generally have small flow rates, and large-flow high and low temperature gas mixing is prone to separation of hot and cold gases, resulting in large temperature non-uniformity at the outlet section, which cannot meet the engine inlet temperature non-uniformity (≤1%), affecting the realism of in-flight simulation tests; 3. Traditional mixing devices have large pressure losses due to airflow resistance. For large-flow mixing, excessive pressure loss increases operating costs and may even lead to situations where the gas supply capacity cannot meet the required operating conditions.

[0007] Existing or under-construction equipment is constrained by construction space, with compact gas supply pipeline layouts and short straight pipe sections at the front end of the mixing device. This results in gas separation or vortices entering the mixing device, and extremely uneven intake airflow, leading to poor mixing performance. The mixed airflow field fails to meet the requirements of in-flight environmental simulation tests, thus affecting the conduct of engine in-flight environmental simulation tests. Therefore, it is necessary to design a device that can achieve efficient and uniform mixing of high and low temperature gases under short-distance, low-flow-resistance conditions to meet the stringent requirements of in-flight simulation tests in compact spaces. Summary of the Invention

[0008] In view of this, the present invention provides a mixing device for simulating large flow rates of high and low temperature gases in the air environment, in order to solve the problems of poor temperature uniformity, excessive pressure loss, and poor mixing effect in the mixing of large flow rates of high and low temperature gases in existing experimental equipment.

[0009] This invention provides the following technical solution: a mixing device for simulating large flow rates of high and low temperature gases in an air environment, comprising: a T-shaped pipe including a first inlet, a second inlet, and a confluence outlet; an airflow stratification baffle that vertically divides the internal space of the T-shaped pipe into at least two independent gas flow paths; and a high and low temperature baffle disposed in the gas flow path and used to block the passage of gas through the first inlet or the second inlet in the gas flow path, wherein the high and low temperature baffle allows the first inlet and the second inlet in the adjacent two gas flow paths to alternately connect with the confluence outlet.

[0010] Compared with the prior art, the beneficial effects that the at least one technical solution adopted by the present invention can achieve include at least the following: 1. Overcoming spatial limitations to achieve efficient short-distance mixing. Compared with traditional mixing principles, the mixing device proposed in this invention uses a stratified approach where one airflow (low temperature) and two airflows (high temperature) enter the mixing device, forming a high-low-high alternating airflow distribution. Two layers of corrugated plate structures are added at the outlet of the mixing device for secondary mixing. This not only fundamentally changes the mixing mechanism of the natural flow of gas in traditional long-distance gas supply pipelines, but also spatially enhances the heat exchange process, effectively improving mixing efficiency and solving the problem of insufficient straight pipe sections at the front end caused by spatial limitations.

[0011] 2. Compared with traditional mixing devices, the crescent-shaped inclined baffle ensures improved mixing efficiency while reducing pressure loss. The high and low temperature baffle blocks the high and low temperature airflow in the main mixer, effectively preventing the high and low temperature gases from mixing in the cavity at the rear of the main mixer. This avoids the large mass airflow from rushing into the flow path of the small mass airflow when the two flow rates differ significantly, thus improving the flow distribution at the mixer outlet.

[0012] 3. When the mixing device proposed in this invention is working, both airflows enter the mixing device through different regions, achieving the purpose of initial rectification, flow fragmentation and flow uniformity of the airflow, and effectively reducing the turbulence of the incoming flow. Then, the flow field is further uniformized through the pipeline at the rear end of the mixing device, which can quickly achieve the temperature non-uniformity (≤1%) of the engine inlet flow field quality within a short distance.

[0013] 4. Compared with the traditional blending device structure, the blending device structure proposed in this invention is a combined structure. If equipment maintenance is required during operation, only the damaged parts need to be maintained or replaced, which greatly improves the maintainability of the equipment. Attached Figure Description

[0014] To more clearly illustrate the technical solutions of the embodiments of this application, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0015] Figure 1 This is the overall structural diagram of the blending device; Figure 2 This is a distribution diagram of two layers of corrugated plates.

[0016] Figure 3 This is a schematic diagram of the distribution of airflow stratification baffles and high / low temperature baffles.

[0017] Figure 4 This is a diagram of the wave plate layout.

[0018] The attached diagram is labeled as follows: 1. T-shaped pipe; 2. Airflow stratification baffle; 3. Crescent-shaped inclined baffle; 4. High and low temperature baffle; 5. Corrugated plate assembly. Detailed Implementation

[0019] The embodiments of this application will now be described in detail with reference to the accompanying drawings.

[0020] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0021] like Figures 1 to 4As shown, this embodiment provides a high-efficiency mixing device for high-flow-rate high- and low-temperature gases in airborne environment simulation. It is suitable for high- and low-temperature gas mixing scenarios with flow rates ranging from 70 kg / s to 1570 kg / s and total temperatures from 203.15 K to 293.15 K, and is particularly well-suited to the high-flow-rate gas supply requirements of civil aviation engine airborne simulation tests. Based on a T-shaped pipe body, the device achieves mixing effects with temperature non-uniformity ≤1%, pressure non-uniformity ≤1%, and turbulence ≤±1% under short-distance (more than 60% shorter straight pipe length compared to traditional devices) and low flow resistance conditions. This solves the technical problems of low mixing efficiency, high pressure loss, and poor spatial adaptability of existing devices.

[0022] In this embodiment, all structural components are made of 304 stainless steel with a surface roughness Ra≤12.5μm, which can withstand the temperature and pressure shocks under all working conditions of the air environment simulation test, ensuring the long-term stable operation of the device.

[0023] T-shaped pipe 1 is an integral welded structure, including a first inlet (for introducing high-temperature gas, corresponding to flow path II), a second inlet (for introducing low-temperature gas, corresponding to flow path I), and a confluence outlet (for outputting the mixed and uniform airflow). The inner diameter of the pipe is designed to fit the maximum flow rate of 1570 kg / s, ensuring smooth and unobstructed airflow.

[0024] All three ports of T-type pipe 1 adopt flange connection structure, which facilitates docking with the test bench air supply network and engine air intake pipe. The flange sealing surface adopts concave-convex surface design, which has excellent sealing performance and can avoid the decrease in mixing accuracy caused by high and low temperature gas leakage.

[0025] The airflow stratification baffle 2 includes horizontal and vertical baffles, both made of 304 stainless steel plates with a thickness of 10mm. It is fixed to the inner wall of the T-shaped pipe 1 by argon arc welding, and the strength grade of the welded joint is not lower than the first-class weld standard specified in GB / T985.1-2008.

[0026] Two horizontal partition plates are evenly arranged vertically along the interior space of the T-shaped pipe 1, dividing the interior of the pipe into three independent gas flow paths (i.e., the first gas flow path, the second gas flow path, and the third gas flow path). The flow cross-sectional area of ​​each flow path is equal (error ≤ ±2%), ensuring that the airflow distribution of each layer is uniform.

[0027] Several vertical partition plates are evenly arranged along the airflow direction within each gas flow path, dividing each flow path into multiple independent cavities (in this embodiment, each layer is divided into 6 cavities), with each cavity having a roughly equal flow area. The function of the vertical partition plates is to cut off the large eddies generated during the upstream flow of the airflow, reduce the turbulence of the incoming flow, and at the same time reduce airflow impact losses through guiding the flow.

[0028] The high and low temperature baffle 4 is made of 304 stainless steel plate, 15mm thick, and is welded and fixed to the airflow stratification baffle 2 and the inner wall of the T-shaped pipe 1. The weld is tight and gapless, ensuring complete blockage of gas passage through the corresponding inlet. Its specific installation location is as follows: In the first gas flow path, the high and low temperature baffle 4 is set on the side close to the second inlet (low temperature gas flow inlet), completely blocking the gas inlet passage of the second inlet in this flow path, so that the first gas flow path is only connected to the first inlet (high temperature gas flow inlet), and only high temperature gas is allowed to pass through; In the second gas flow path, the high and low temperature baffle 4 is set on the side close to the first inlet (high temperature gas flow inlet), completely blocking the first inlet's air intake passage in this flow path, so that the second gas flow path is only connected to the second inlet (low temperature gas flow inlet), and only low temperature gas is allowed to pass through; In the third gas flow path, the high and low temperature baffle 4 is set in the same way as the first gas flow path, that is, it blocks the air intake channel of the second inlet and only allows high temperature gas to pass through.

[0029] The above arrangement creates an alternating "high temperature - low temperature - high temperature" airflow within the T-shaped pipe 1, laying the foundation for efficient mixing in the future. It also avoids the problem of a large mass airflow rushing into the small mass airflow path when the two flow rates differ significantly, thus improving the uniformity of the outlet flow distribution.

[0030] The crescent-shaped inclined baffle 3 is made of 304 stainless steel plate with a thickness of 20mm. It is set between the outermost vertical partition plate and the inner wall of the T-shaped pipe 1, specifically outside the airflow convergence area of ​​the first and second inlets.

[0031] The crescent-shaped inclined baffle 3 is inclined at a 45° angle to the axis of the corresponding first or second inlet, with its arc-shaped surface facing the direction of the incoming airflow and its flat side forming a gas guiding inclined surface facing the direction of the airflow stratification baffle 2. This structural design can guide the airflow smoothly into each layer of the flow path along the guiding inclined surface, avoiding direct collision of airflow at the rear end of the main mixer. Compared with the traditional flat baffle, it can reduce the pressure loss by 227 Pa and significantly reduce the operating energy consumption.

[0032] The connection between the crescent-shaped inclined baffle 3 and the inner wall of the T-shaped pipe 1 and the vertical partition plate is made by argon arc welding. During welding, ensure that the tilt angle error of the guide slope is ≤±1° to avoid airflow deflection and flow field disturbance due to angle deviation.

[0033] The corrugated plate assembly 5 is located at the confluence outlet of the T-shaped pipe 1, outside the outlet of the gas flow path. It is used to further enhance the mixing of the initially mixed gas flow, thereby improving temperature uniformity. This assembly consists of two layers arranged sequentially along the gas outlet direction, as shown in the following structure: The support plate is made of 304 stainless steel sheet without vertical splicing, with a thickness of 15mm. It is fixedly connected to the flange end face of the confluence outlet by argon arc welding. The installation position of the support plate corresponds one-to-one with the outlet position of the gas flow path to ensure that all airflow can pass through the corrugated plate assembly 5. The corrugated plate body has an S-shaped structure and is formed by stamping 8mm thick 304 stainless steel plate. The radius of curvature is optimized according to the airflow velocity (150mm in this embodiment). Six independent corrugated plate bodies are arranged at intervals on each support plate. Each corrugated plate body corresponds to a cavity in a gas flow path. A 10mm gap is left between adjacent corrugated plate bodies (to reduce airflow resistance). The two corrugated plate assemblies 5 are arranged in a non-uniform manner with vertical symmetry. The upper and lower corrugated plate bodies are staggered to further enhance the mixing effect.

[0034] The upper end of each wave plate is welded and fixed to the support plate, and the lower end is positioned by a limiting block (the limiting block is welded to the support plate) to ensure that the wave plate body does not deform or shift under the impact of high-speed airflow, thus ensuring the stability of the mixing effect.

[0035] The processing, fabrication, and assembly of the blending device of this invention strictly follow the following steps to ensure structural accuracy and assembly quality.

[0036] Material pretreatment: All 304 stainless steel plates, pipes and fasteners are degreased and derusted to ensure welding quality. The surface roughness Ra after treatment is ≤12.5μm. T-shaped pipe processing: Cut the pipe according to the design dimensions, form it with a plate rolling machine and weld it into a T-shaped structure. After welding, perform non-destructive testing (UT+RT) to ensure that there are no welding defects. The inner wall of the pipe is polished smooth, without protrusions or burrs. Airflow stratification baffle installation: First, weld the horizontal baffle to the inner wall of the T-shaped pipe 1 at a predetermined interval, then install the vertical baffle in each flow path to ensure that the flow area of ​​each cavity is uniform. After welding, clean the excess height of the weld. High and low temperature baffle installation: According to the sealing requirements of the first, second and third gas flow paths, the high and low temperature baffle 4 is positioned in the designated position and fully welded to the horizontal baffle, vertical baffle and the inner wall of the pipe. After welding, the air tightness test is carried out to ensure that there is no gas leakage. Installation of the crescent-shaped inclined baffle: Position the prefabricated crescent-shaped inclined baffle 3 at a 45° angle and weld it to the inner wall of the pipe and the outermost vertical partition plate. During the welding process, use an angle gauge to monitor in real time to ensure that the tilt angle error is ≤±1%. Corrugated plate assembly installation: First, weld and fix the support plate to the end face of the confluence outlet flange. Then, insert the S-shaped corrugated plate body horizontally into the mounting groove of the support plate and fix the lower end with the limit block to ensure that the spacing of the corrugated plate body is uniform and the installation is firm. Overall inspection: After assembly, the device is checked for overall dimensions, airtightness, and flow channel unobstructedness to ensure that all structures meet the design requirements and are free from defects that affect airflow.

[0037] The mixing device of the present invention achieves efficient and uniform mixing through a three-stage mixing mechanism of "layered flow guidance - anti-countercurrent drag reduction - secondary enhanced mixing", the specific process of which is as follows: First-level stratified flow guidance: High-temperature gas (path II) enters from the first inlet of T-shaped pipe 1, and low-temperature gas (path I) enters from the second inlet. It is divided into three flow paths by the horizontal partition of the airflow stratification baffle 2, and then divided into multiple independent cavities by the vertical partition. At the same time, through the alternating blocking of high and low temperature baffles 4, an alternating distribution of "high temperature-low temperature-high temperature" airflow is formed, which realizes the initial rectification, fragmentation and uniform flow of the airflow, and reduces the turbulence of the incoming flow. Secondary anti-collision drag reduction: The crescent-shaped inclined baffle 3 guides the staggered high and low temperature airflows to smoothly converge along the 45° guide inclined surface, avoiding the flow field turbulence and pressure loss caused by direct airflow collision, while further streamlining the flow field; Three-stage secondary mixing: After preliminary mixing, the airflow enters the two-layer corrugated plate assembly 5 at the confluence outlet. The S-shaped corrugated plate body breaks up the large-area concentrated high and low temperature gas region, causing the airflow to generate flow around and shear under the guidance of the corrugated plate, enhancing heat exchange and mass exchange, and finally achieving efficient and uniform mixing. The mixed airflow is output to the engine intake pipe through the confluence outlet.

[0038] To verify the mixing effect of the device in this embodiment, aerodynamic simulation tests were conducted under typical operating conditions, and the performance under different flow rates was also tested. The specific verification data are as follows: To verify the influence of the structure of each part of the device of the present invention on the mixing effect, an actual working condition was selected for aerodynamic simulation, as shown in Table 1.

[0039] Table 1

[0040] Based on the operating conditions in Table 1, the influence of the structure of each part of the blending device on the blending effect was verified. The non-uniformity of the outlet temperature was calculated, and the non-uniformity of the three blending devices at the outlet was 34.31%, 34.02%, and 31.48%, respectively (see Table 2). The non-uniformity of the engine inlet temperature was 5.74%, 3.79%, and 0.9945%, respectively. It can be seen that the crescent-shaped baffle and the corrugated plate at the outlet can effectively improve the non-uniformity of the outlet temperature of the blending device, meeting the requirement of engine inlet temperature non-uniformity (≤1%).

[0041] Table 2

[0042] To verify the mixing effect of the mixing device under different operating conditions, three typical operating conditions were selected: low flow rate, medium flow rate, and high flow rate mixing. The specific inlet parameters are shown in Table 3.

[0043] Table 3

[0044] As shown in Table 3, the mixing effect of the mixing device is not significantly different under the three flow conditions. The mixing effect is best under the high flow condition. Only a short straight section of pipe is needed to meet the requirement that the temperature non-uniformity is within 1%. It can achieve the mixing of high-flow-rate high and low temperature airflows in a limited space with good results.

[0045] The above description is merely a specific embodiment of the present invention and should not be construed as limiting the scope of the invention. Therefore, any substitution of equivalent components or equivalent changes and modifications made within the scope of protection of this patent should still fall within the scope of this patent. Furthermore, the technical features, technical features and technical solutions, and technical solutions in this invention can be freely combined and used.

Claims

1. A mixing device for simulating high-volume, low-temperature gases in an airborne environment, characterized in that, include: The T-shaped pipe (1) includes a first inlet, a second inlet, and a confluence outlet; The airflow stratification baffle (2) divides the internal space of the T-shaped pipe (1) vertically into at least two independent gas flow paths; The high and low temperature baffle (4) is set in the gas flow path and is used to block the gas from passing through the first or second inlet in the gas flow path. Through the high and low temperature baffle (4), the first and second inlets in the gas flow paths of the two adjacent layers are alternately connected to the confluence outlet.

2. The mixing device for simulating high-volume, low-temperature gases in an airborne environment according to claim 1, characterized in that, The airflow stratification baffle (2) includes a horizontal baffle and a vertical baffle. The horizontal baffle divides the internal space of the T-shaped pipe (1) into at least two independent gas flow paths in the vertical direction. The vertical baffle divides each gas flow path into multiple independent cavities.

3. The mixing device for simulating high-flow-rate high- and low-temperature gases in an airborne environment according to claim 2, characterized in that, The internal space of the T-shaped pipe (1) is divided into a first gas flow path, a second gas flow path and a third gas flow path by a horizontal partition. In the first gas flow path, a high and low temperature partition (4) is set on the side near the second inlet and is used to block the gas intake at the second inlet. In the second gas flow path, a high and low temperature partition (4) is set on the side near the first inlet and is used to block the gas intake at the first inlet. In the third gas flow path, a high and low temperature partition (4) is set on the side near the second inlet and is used to block the gas intake at the second inlet.

4. The mixing device for simulating high-volume high- and low-temperature gases in an airborne environment according to claim 2, characterized in that, The air environment simulation high-flow-rate high- and low-temperature gas mixing device also includes: a crescent-shaped inclined baffle (3), which is set between the outermost vertical partition plate and the inner wall of the T-shaped pipe (1).

5. The mixing device for simulating high-flow-rate high- and low-temperature gases in an airborne environment according to claim 4, characterized in that, The crescent-shaped inclined baffle (3) is inclined between the axis of the corresponding first inlet or second inlet, and the crescent-shaped inclined baffle (3) forms a gas guiding inclined surface toward the airflow stratification baffle (2).

6. The mixing device for simulating high-flow-rate high- and low-temperature gases in an airborne environment according to claim 1, characterized in that, A corrugated plate assembly (5) is provided at the confluence outlet, located outside the outlet of the gas flow path.

7. The mixing device for simulating high-flow-rate high- and low-temperature gases in an airborne environment according to claim 6, characterized in that, The wave plate assembly (5) includes A support plate is fixedly connected to the confluence outlet, and the position of the support plate corresponds to the outlet position of the gas flow path; The wave plate body is mounted on the support plate.

8. The mixing device for simulating high-flow-rate high- and low-temperature gases in an airborne environment according to claim 7, characterized in that, The support plate is multi-layered, and each layer of the support plate is equipped with multiple wave plate bodies, which are spaced apart.

9. The mixing device for simulating high-flow-rate high- and low-temperature gases in an airborne environment according to claim 6, characterized in that, The wave plate assembly (5) consists of multiple sets, arranged sequentially along the air outlet direction.

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