Combustion type air heater for ground direct connection type test bench

Abstract

The invention discloses a combustion type air heater for a ground direct connection type test bed. The combustion type air heater comprises a combustion chamber, a switching section, a tail spray pipe, a fuel gas injector, an air-oxygen mixed gas injector, an air-oxygen mixer, a main fuel gas nozzle and an auxiliary fuel gas nozzle. The fuel gas injector, the air-oxygen mixed gas injector, the combustion chamber, the switching section and the exhaust nozzle are sequentially connected, part of the area of the bottom of the air-oxygen mixed gas injector serves as an injection panel, and the main fuel gas nozzle penetrates through the fuel gas injector and the air-oxygen mixed gas injector and is inserted into an air nozzle of the injection panel. A first circular seam is formed between the main gas nozzle and the air nozzle; a plurality of auxiliary gas nozzles are uniformly distributed around the main gas nozzle, the auxiliary gas nozzles are inserted into the air nozzles at the corresponding positions of the injection panel, and second circular seams are formed between the auxiliary gas nozzles and the air nozzles; and the main gas nozzle and the air-oxygen mixed gas filler are respectively connected with the positive electrode and the negative electrode of the high-voltage electric spark generator. The heater has the characteristics of large temperature span, novel structure, integrated ignition and the like.

Description

Technical Field

[0001] The invention belongs to the technical field of aerospace test equipment, and particularly relates to a combustion-type air heater for a ground direct-connection test bench. Background Art

[0002] The direct-connection test bench has the advantages of easy parameter adjustment, high test efficiency, high safety, etc., and is a very important ground test bench in the aerospace field. Its working principle is to directly connect the combustion chamber of an aeroengine behind an experimental device that simulates the oncoming flow of high-altitude flight, and by manually adjusting the parameters of the experimental device, the airflow parameters entering the combustion chamber, such as velocity, composition, pressure, etc., can simulate the airflow parameters of actual high-altitude flight.

[0003] Currently, the experimental devices for simulating the oncoming flow of high-altitude flight mainly include three types: vacuum self-aspirating wind tunnels, regenerative heaters, and combustion-type heaters. The vacuum self-aspirating wind tunnel requires a huge vacuum sphere and supporting vacuum pumping equipment to be installed behind the test section, resulting in a relatively high construction cost of the test bench. The highest temperature of the regenerative heater disclosed in the literature "Progress in the Design and Construction of a 1m-class Hypersonic Wind Tunnel in the Aviation Industry" is 900K, with huge power consumption and high cost. See "Gao Liangjie, Xin Yanan, etc. Progress in the Design and Construction of a 1m-class Hypersonic Wind Tunnel in the Aviation Industry [J]. Experimental Fluid Mechanics, 2022, 36(01): 44-51". For the combustion-type heater, the invention patent with the application number 201710260853.2 discloses an air heating device for a ground direct-connection test of an aeroengine, with an operating temperature of 600 - 1500K, a relatively small temperature span, and the need for oxygen supplementation in the middle section of the combustion chamber, which not only increases the complexity of the pipeline, but also raises the equipment and control costs; due to the existence of the oxygen supplementation structure, the combustion chamber cannot be equipped with a water cooling system, and multiple long-term tests will cause serious heat accumulation on the test bench, shortening the equipment life and posing safety hazards.

[0004] Existing combustion-type heaters usually need to be equipped with an igniter separately for starting the heater, which means that a separate gas supply system and measurement and control system need to be set up, obviously increasing the complexity and cost of the equipment. Since the separately equipped igniter needs to penetrate the outer air to contact the fuel for ignition when starting the heater, and the air flow rate is quite large under low total temperature conditions, not only is the flame generated by the igniter often difficult to penetrate the air, but also the air flow on the injection panel is severely disturbed, making the flame difficult to stabilize. This is also the key reason why existing combustion-type heaters usually have difficulty in achieving stable operation below a total temperature of 900K. Currently, for combustion-type heaters that can span a large total temperature range, usually two or more injection panels are required for different total temperature intervals, and the equipment needs to be disassembled and replaced to a large extent during variable condition tests, which not only increases the test time and cost, but also the frequent disassembly and assembly will shorten the equipment life. Summary of the Invention

[0005] In view of the deficiencies of the prior art, the technical problem to be solved by the present invention is to provide a combustion-type air heater for a ground direct-connected test bench, so as to solve the problems of complex structure, high test cost and small temperature span of the existing air heater.

[0006] The present invention adopts the following technical solutions to solve the above-mentioned technical problems: A combustion-type air heater for a ground direct-connected test bench, comprising a combustion chamber, a transition section, a tail nozzle, a fuel injector, an air-oxygen mixture injector, an air-oxygen mixer, a main fuel nozzle and an auxiliary fuel nozzle; Part of the area at the bottom of the air-oxygen mixture injector serves as a jet panel, and a plurality of air nozzles are arranged on the jet panel; the fuel injector, the air-oxygen mixture injector, the combustion chamber, the transition section and the tail nozzle are connected in sequence; the main fuel nozzle penetrates through the fuel injector and the air-oxygen mixture injector and is inserted into the air nozzle at the center position of the jet panel, and a first annular gap is formed between the main fuel nozzle and the air nozzle; a plurality of auxiliary fuel nozzles are evenly distributed around the main fuel nozzle, and each auxiliary fuel nozzle is inserted into the air nozzle at the corresponding position of the jet panel, and a second annular gap is formed between the auxiliary fuel nozzle and the air nozzle; the main fuel nozzle and the air-oxygen mixture injector are respectively connected to the positive and negative electrodes of a high-voltage electric spark generator.

[0007] Further, a fuel chamber is provided in the middle of the fuel injector, and a plurality of fuel injection holes communicating with the fuel chamber are provided at the top.

[0008] Further, an air-oxygen mixture chamber is provided in the middle of the air-oxygen mixture injector, air-oxygen mixture injection holes communicating with the air-oxygen mixture chamber are provided around, and the area at the bottom of the air-oxygen mixture injector facing the air-oxygen mixture chamber serves as a jet panel.

[0009] Further, a plurality of radial fuel inlets are evenly provided around the middle of the main fuel nozzle, and the fuel inlets communicate with the main flow channel of the main fuel nozzle along the axis.

[0010] Further, a fuel inlet is provided at the top of the main fuel nozzle, and the fuel inlet communicates with the main flow channel of the main fuel nozzle along the axis.

[0011] Further, the air-oxygen mixer includes an air pipe and an oxygen pipe; air holes are evenly arranged in the circumferential direction at the waist of the air pipe, an oxygen chamber covering all the air holes is covered outside the waist of the air pipe, and the oxygen pipe is connected to the oxygen chamber.

[0012] Further, the combustion chamber and the tail nozzle are both provided with water-cooled jackets.

[0013] Further, the transition section is provided with parameter measurement holes for measuring the total temperature and total pressure of the combustion chamber.

[0014] Furthermore, the upper and lower parts of the main gas nozzle are fixedly connected to the gas injector and the air-oxygen mixture injector respectively through insulating sleeves.

[0015] Compared with the prior art, the present invention has the following beneficial effects: 1. The main gas nozzle, the gas injector, the air-oxygen mixture injector and the auxiliary gas nozzle jointly form a novel heater head cavity structure. Annular gaps are formed between the main gas nozzle and the auxiliary gas nozzle and the air nozzles of the injection panel respectively. The air-oxygen mixture is ejected from the annular gaps. The main gas nozzle realizes ignition through the tip discharge effect, which can effectively avoid the ablation of the injection panel caused by the high-temperature area on the panel, and directly realizes integrated ignition on the injection panel without the need to separately configure an igniter, reducing the complexity and cost of the equipment. The applicable total temperature range of this air heater is 400K - 2500K, solving the problem of small total temperature span of the existing heaters.

[0016] 2. The main gas nozzle has two configurations, which are applicable to different total temperature ranges, and the connection between the main gas nozzle and the gas injector and the air-oxygen mixture injector is convenient, making it easy to disassemble, install and replace during the tests of different total temperature ranges.

[0017] 3. Under the low total temperature condition, the air flow rate is large, and under the high total temperature condition, the air flow rate is small. The requirements for the number and size of the air nozzles on the injection panel are different for the two conditions. Therefore, in the condition of large temperature span, the existing combustion-type air heaters need to replace different injection panels to adapt to the total temperature range. However, the present invention only needs one injection panel to achieve the condition of large temperature span, which is not only simple in structure but also avoids frequent disassembly, installation and replacement of the equipment.

[0018] 4. The air-oxygen mixer can evenly mix air and oxygen, making the combustion flame more stable, eliminating the need to add an oxygen supplement device in the rear section of the combustion chamber, simplifying the overall structure, reducing the cost, and at the same time ensuring the integrity of the combustion chamber structure, enabling it to install a water cooling system to ensure that the combustion chamber will not overheat during the long-term operation of the heater, extending the equipment life and improving the safety.

[0019] 5. The transition section is not only used to connect the combustion chamber and the tail nozzle, but also provided with parameter measurement holes for measuring the total temperature and total pressure of the combustion chamber, avoiding the method of measuring the total pressure and total temperature by facing the wind to measure the pressure, improving the safety. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 is the overall structure diagram of the present invention; Figure 2 is the structure diagram of the injection panel of the present invention; Figure 3 is a structure diagram of one kind of the main gas nozzle of the present invention; Figure 4 Another structural diagram of the main gas nozzle of the present invention; Figure 5 Structural diagram of the air-oxygen mixer of the present invention; Description of the drawings: 1 - main gas nozzle; 2 - gas injector; 3 - air-oxygen mixture injector; 4 - combustion chamber; 5 - transition section; 6 - tail nozzle; 7 - air-oxygen mixer; 8 - auxiliary gas nozzle; 9 - first insulating sleeve; 10 - second insulating sleeve; 11 - third insulating sleeve; 12 - compression flange; 13 - sealing gasket; 21 - gas injection hole; 22 - gas chamber; 31 - air-oxygen mixture injection hole; 32 - air-oxygen mixture chamber; 41 - water-cooled outlet of the combustion chamber; 42 - water-cooled inlet of the combustion chamber; 51 - parameter measurement hole; 61 - water-cooled outlet of the nozzle; 62 - water-cooled inlet of the nozzle; 71 - oxygen pipeline; 72 - oxygen chamber; 73 - air pipeline. Detailed implementation manners

[0021] The following provides specific embodiments in conjunction with the drawings. The specific embodiments are only used to introduce the technical solution of the present invention in detail and do not limit the protection scope of this application.

[0022] The present invention is a combustion-type air heater for a ground direct-connected test bench, including a main gas nozzle 1, a gas injector 2, an air-oxygen mixture injector 3, a combustion chamber 4, a transition section 5, a tail nozzle 6, an air-oxygen mixer 7, an auxiliary gas nozzle 8, a first insulating sleeve 9, a second insulating sleeve 10, a third insulating sleeve 11 and a sealing gasket 13; The top of the gas injector 2 is provided with a plurality of axially arranged gas injection holes 21, the gas injection holes 21 are connected to a gas supply device, and the middle part is provided with a gas chamber 22 communicating with the gas injection holes 21; the middle part of the air-oxygen mixture injector 3 is provided with an air-oxygen mixture chamber 32, and the periphery of the air-oxygen mixture injector 3 is provided with a plurality of radially arranged air-oxygen mixture injection holes 31, the air-oxygen mixture injection holes 31 communicate with the air-oxygen mixture chamber 32, and each air-oxygen mixture injection hole 31 is connected to the air outlet end of the air-oxygen mixer 7; the area at the bottom of the air-oxygen mixture injector 3 facing the air-oxygen mixture chamber 32 serves as a jet panel (see Figure 2 )), and a plurality of air nozzles are evenly arranged on the jet panel; The fuel injector 2, the air-oxygen mixture injector 3, the combustion chamber 4, the transition section 5 and the tail nozzle 6 are connected in sequence. Sealing gaskets 13 are respectively provided between the air-oxygen mixture injector 3 and the fuel injector 2 and the combustion chamber 4; The main fuel nozzle 1 is located at the central positions of the fuel injector 2 and the air-oxygen mixture injector 3. After passing through the fuel injector 2 and the air-oxygen mixture injector 3 in sequence, it is inserted into the air nozzle at the central position of the injection panel. A first annular gap is formed between the outer wall of the main fuel nozzle 1 and the inner wall of the air nozzle. The air-oxygen mixture sprays out from the first annular gap and mixes with the fuel sprayed out from the main fuel nozzle 1. The main fuel nozzle 1, the fuel injector 2, the air-oxygen mixture injector 3 and the auxiliary fuel nozzle 8 together form the head cavity of the heater; Further, the upper part of the main fuel nozzle 1 is hermetically connected to the fuel injector 2 through the second insulating sleeve 10. The head of the main fuel nozzle 1 is connected to the compression flange 12 through the first insulating sleeve 9. The compression flange 12 is fixedly connected to the end of the fuel injector 2 by screws. The lower part of the main fuel nozzle 1 is connected to the air-oxygen mixture injector 3 through the third insulating sleeve 11; A plurality of auxiliary fuel nozzles 8 (four in this embodiment) are evenly distributed around the main fuel nozzle 1. The auxiliary fuel nozzles 8 are inserted from the end face of the air-oxygen mixture injector 3. After passing through the air-oxygen mixture injector 3, they are inserted into the air nozzles at the corresponding positions of the injection panel. The air inlet of the auxiliary fuel nozzle 8 is communicated with the fuel cavity 22 of the fuel injector 2. The air outlet of the auxiliary fuel nozzle 8 is communicated with the combustion chamber 4. A second annular gap is formed between the outer wall of the auxiliary fuel nozzle 8 and the inner wall of the air nozzle. The air-oxygen mixture sprays out from the second annular gap and mixes with the fuel sprayed out from the auxiliary fuel nozzle 8; The main fuel nozzle 1, the auxiliary fuel nozzle 8, the air-oxygen mixture injector 3, the combustion chamber 4, the transition section 5 and the tail nozzle 6 are all made of 304 stainless steel; The main fuel nozzle 1 is connected to the positive pole of the high-voltage electric spark generator, and the air-oxygen mixture injector 3 is connected to the negative pole of the high-voltage electric spark generator. When the high-voltage electric spark generator is powered on, through the tip discharge effect, a high-voltage electric spark is generated at the first annular gap formed between the main fuel nozzle 1 and the corresponding air nozzle, ionizing and activating the air-oxygen mixture sprayed out from the first annular gap, and then igniting the fuel sprayed out from the main fuel nozzle 1 and forming a high-temperature flame at the main fuel nozzle 1. The flame quickly spreads to the auxiliary fuel nozzle 8 and ignites the fuel sprayed out from the auxiliary fuel nozzle 8 to achieve ignition; The fuel burns in the combustion chamber 4 to generate high-temperature flue gas. The high-temperature flue gas enters the tail nozzle 6 through the transition section 5, accelerates and expands in the tail nozzle 6, and then enters the combustion chamber of the downstream aeroengine.

[0023] The main fuel nozzle 1 is divided into two configurations, suitable for different total temperature ranges. Such as Figure 3As shown, in one configuration, a plurality of radial gas inlets are evenly arranged around the middle of the main gas nozzle 1. The gas inlets are communicated with the main flow channel along the axial direction of the center of the main gas nozzle 1. The total temperature range applicable to this kind of main gas nozzle 1 is 400K - 1600K. During installation, it is necessary to ensure that the gas inlets of the main gas nozzle 1 are communicated with the gas cavity 22 of the gas injector 2, so that the main gas nozzle 1 and the auxiliary gas nozzle 8 share the gas cavity 22. As Figure 4 shown, in another configuration, the gas inlet of the main gas nozzle 1 is located at the top. The gas inlet is communicated with the main flow channel along the axial direction of the center. The gas inlet is connected to the gas supply device, and the gas supply device supplies gas independently to the main gas nozzle 1. The total temperature range applicable to this kind of main gas nozzle 1 is 1600K - 2500K.

[0024] As Figure 5 shown, the air-oxygen mixer 7 includes an air pipeline 73 and an oxygen pipeline 71. A circle of air holes is evenly arranged in the circumferential direction at the waist of the air pipeline 73. An oxygen cavity 72 is coated on the outside of the waist of the air pipeline 73, and the oxygen cavity 72 covers all the air holes. The oxygen pipeline 71 is connected to the oxygen cavity 72. Oxygen enters the oxygen cavity 72 through the oxygen pipeline 71, and then enters the air pipeline 73 through the air holes to be mixed with air to form air-oxygen mixture.

[0025] The outer wall of the combustion chamber 4 is provided with a water-cooled jacket. A plurality of combustion chamber water-cooled outlets 41 and combustion chamber water-cooled inlets 42 are provided on the water-cooled jacket. The combustion chamber 4 is cooled by water-cooling to ensure that the combustion chamber 4 will not overheat and can operate for a long time multiple times.

[0026] The adapter section 5 is connected to the combustion chamber 4 and the tail nozzle 6 by means of flange connection to realize the transition between the combustion chamber 4 and the tail nozzle 6. A graphite gasket is used to realize the sealing between the adapter section 5 and the combustion chamber 4 and the tail nozzle 6. Two parameter measurement holes 51 are opened on the adapter section 5 for measuring the total temperature and total pressure of the combustion chamber 4.

[0027] The function of the tail nozzle 6 is to accelerate and expand the high-temperature flue gas generated by combustion to the required flight Mach number. The contraction profile can be designed according to the requirements of the flight Mach number to produce a better acceleration and expansion effect. The tail nozzle 6 is provided with a water-cooled jacket. A plurality of nozzle water-cooled outlets 61 and nozzle water-cooled inlets 62 are provided on the water-cooled jacket to ensure that the tail nozzle 6 will not overheat and can operate stably for a long time multiple times.

[0028] The first insulating sleeve 9, the second insulating sleeve 10 and the third insulating sleeve 11 are made of polytetrafluoroethylene. Polytetrafluoroethylene has a high breakdown voltage and good compression and self-sealing properties. Therefore, it can realize the sealing and insulation between the main gas nozzle 1 and the gas injector 2 and the air-oxygen mixture injector 3.

[0029] Example 1: Set the total temperature to 400K, flight Mach number to 2, incoming flow Mach number to 0.7, and the main gas nozzle 1 adopts Figure 3 the structure shown. The gas enters the gas chamber 22 through the gas filling holes 21 on the gas filler 2. Part of the gas enters the main gas nozzle 1 through the gas inlet of the main gas nozzle 1, and the other part of the gas enters each sub-gas nozzle 8. The main gas nozzle 1 and the sub-gas nozzles 8 jointly inject gas into the combustion chamber 4. Air and oxygen are mixed in the air-oxygen mixer 7 to form an air-oxygen mixture, which enters the air-oxygen mixture chamber 32 through the air-oxygen mixture filling holes 31 on the air-oxygen mixture filler 3, and then enters the combustion chamber 4 through the air nozzles on the injection panel; the high-voltage electric spark generator is powered on, and through the tip discharge effect, a high-voltage electric spark is generated at the first annular gap formed by the main gas nozzle 1 and the corresponding air nozzle, ionizing and activating the air-oxygen mixture ejected from the first annular gap, igniting the gas ejected from the main gas nozzle 1 and forming a high-temperature flame at the main gas nozzle 1. The flame quickly spreads to the sub-gas nozzle 8 and ignites the gas ejected from the sub-gas nozzle 8 to achieve ignition. At this time, the heater starts; since the total temperature is relatively low at the initial stage of startup, it is difficult for the gas to be directly ignited in the air-oxygen mixture. Therefore, oxygen needs to be introduced through the air-oxygen mixer 7 for ignition first, and then air is introduced for afterburning and cooling the high-temperature flue gas. The ignition timing is as follows: Start the high-voltage electric spark generator at 0s and introduce oxygen at 0.5s; Introduce gas at 1s, and at this time the gas is mixed with oxygen to achieve ignition; Introduce air at 2s. After the air is added, the total temperature of the high-temperature flue gas generated by combustion drops to the set temperature of 400K, and the heater starts to operate according to the set working conditions; Turn off the high-voltage electric spark generator at 2.5s; Stop introducing gas and oxygen at 7.5s, the flame goes out, and the combustion process ends; Stop introducing air at 9s. Finally, stopping introducing air can blow out the residual high-temperature flue gas in the heater and achieve cooling, and the work ends.

[0030] Example 2: Set the total temperature to 2500K, flight Mach number to 5, incoming flow Mach number to 2. Since the gas flow rate is very large, if Figure 3 the main gas nozzle 1 is used, evenly distributing the flow rate to the main gas nozzle 1 and the sub-gas nozzles 8 will cause the gas flow velocity at the outlet of the gas nozzle to be too high, making it difficult to achieve stable ignition. Therefore, the main gas nozzle 1 adopts Figure 4 the structure shown. The gas is divided into two paths and enters the combustion chamber 4. One path directly enters through the main gas nozzle 1. The gas ejected from the main gas nozzle 1 meets the air-oxygen mixture at the first annular gap. When the equivalence ratio is 0.9 - 2, the ignition success rate can be guaranteed; the other path of gas enters the gas chamber 22 of the gas filler 2 and then enters each sub-gas nozzle 8. The ignition of this example does not require introducing oxygen for ignition first. The ignition timing is as follows: Start the high-voltage electric spark generator at 0 s, and introduce oxygen and air at 0.5 s; Introduce fuel gas into the main fuel gas nozzle 1 at 1 s to achieve ignition; Introduce fuel gas into the fuel gas chamber 22 of the fuel gas injector 2 at 1.5 s, and ignite the fuel gas ejected from each auxiliary fuel gas nozzle 8 through the high-temperature flame generated at the main fuel gas nozzle 1. The heater starts completely and operates according to the set working conditions; Turn off the high-voltage electric spark generator at 2 s; stop introducing fuel gas and oxygen at 7 s, the flame goes out, and the combustion process ends; Stop introducing air at 9 s.

[0031] Matters not described in the present invention are applicable to the prior art.

Claims

1. A combustion air heater for a ground direct-connected test bench, comprising a combustion chamber, a transition section and a tail nozzle; characterized in that: It also includes a gas filler, an air-oxygen mixed gas filler, an air-oxygen mixer, a main gas nozzle and an auxiliary gas nozzle; a part of the bottom of the air-oxygen mixed gas filler is used as an injection panel, and a plurality of air nozzles are arranged on the injection panel; The gas filler, air-oxygen mixture filler, combustion chamber, transition section and tail nozzle are connected in sequence; the main gas nozzle penetrates the gas filler and the air-oxygen mixture filler, and is inserted into the air nozzle at the center of the injection panel, and a first annular gap is formed between the main gas nozzle and the air nozzle; multiple auxiliary gas nozzles are evenly distributed around the main gas nozzle, and each auxiliary gas nozzle is inserted from the end face of the air-oxygen mixture filler, penetrates the air-oxygen mixture filler, and is inserted into the air nozzle at the corresponding position of the injection panel, and a second annular gap is formed between the auxiliary gas nozzle and the air nozzle, and the air inlet of the auxiliary gas nozzle is connected to the gas filler; the main gas nozzle and the air-oxygen mixture filler are respectively connected to the positive and negative electrodes of the high-voltage electric spark generator.

2. The combustion type air heater for a ground direct-connected test bench according to claim 1, characterized in that: A gas cavity is arranged in the middle of the gas filler, and a plurality of gas filling holes communicating with the gas cavity are arranged on the top.

3. The combustion type air heater for a ground direct-connected test bench according to claim 1 or 2, characterized in that: An air-oxygen mixture cavity is arranged in the middle of the air-oxygen mixture filler, and air-oxygen mixture filling holes connected to the air-oxygen mixture cavity are arranged around it. The area at the bottom of the air-oxygen mixture filler facing the air-oxygen mixture cavity serves as an injection panel.

4. The combustion type air heater for a ground direct-connected test bench according to claim 1, characterized in that: A plurality of radial gas inlets are evenly arranged around the middle of the main gas nozzle, and the gas inlets are communicated with the main flow channel of the main gas nozzle along the axial direction.

5. The combustion type air heater for a ground direct-connected test bench according to claim 1, characterized in that: A gas inlet is arranged on the top of the main gas nozzle, and the gas inlet is communicated with the main flow channel of the main gas nozzle along the axial direction.

6. The combustion type air heater for a ground direct-connected test bench according to claim 1, 4 or 5, characterized in that: The air-oxygen mixer comprises an air duct and an oxygen duct; the waist of the air duct is uniformly arrayed with air holes in the circumferential direction, the outer side of the waist of the air duct is covered with an oxygen cavity covering all the air holes, and the oxygen duct is connected to the oxygen cavity.

7. The combustion type air heater for a ground direct-connected test bench according to claim 1, characterized in that: The combustion chamber and the tail nozzle are both provided with water cooling jackets.

8. The combustion type air heater for a ground direct-connected test bench according to claim 1, characterized in that: The transition section is provided with parameter measuring holes for measuring the total temperature and total pressure of the combustion chamber.

9. The combustion type air heater for a ground direct-connected test bench according to claim 1, characterized in that: The upper part and the lower part of the main gas nozzle are respectively connected to the gas filler and the air-oxygen mixed gas filler through insulating sleeves.

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