CN106628191A - Mixing chamber applied to airplane environment control system - Google Patents

Abstract

The invention relates to an aircraft environment control system, in particular to a mixing chamber applied to the aircraft environment control system. Two layers of sound-absorbing layers are arranged in the mixing chamber, and the described sound-absorbing layers are aluminum micro-perforated plates. This technical solution makes the mixing uniformity of the gas temperature in the mixing chamber better in the aircraft environment control system, can effectively reduce the airflow noise in the mixing chamber, and can effectively eliminate the condensed water formed in the mixing chamber, so that the air from the mixing chamber is supplied to the cockpit and passenger cabin. Air quality is improved.

Description

A mixing chamber applied to an aircraft environmental control system

technical field

The invention relates to an aircraft environment control system, in particular to a mixing chamber applied to the aircraft environment control system.

Background technique

The mixing chamber is an important part of the environmental control system of the transport aircraft. It mixes the fresh air from the air conditioning unit and the recirculated air from the cabin evenly, and sends them into the cockpit and cabin areas to realize the temperature adjustment of the cockpit and cabin. Due to the difference in temperature and pressure of the two air streams, there will be turbulent flow, vortex, etc. during the mixing process, which will form obvious aerodynamic noise, and condensed water will be precipitated. In addition, the noise generated by the turbine in the upstream refrigeration component of the mixing chamber of the environmental control system will obviously affect the downstream, propagate to the mixing chamber and superimpose the noise generated by the mixing chamber itself, so that the noise problem of the system at the mixing chamber cannot be ignored. Effective control is carried out, and the secondary noise level of the pipeline downstream of the mixing chamber is relatively small, and no separate noise reduction treatment is required.

At present, the design of the mixing chamber in the environmental control system on transport aircraft can generally only ensure the performance of uniform airflow temperature mixing, and there is no noise reduction design itself, so that the airflow noise formed by the system here cannot be controlled in time. For small passenger aircraft, the layout The limited space will make the impact of the noise in the mixing room on the cabin more obvious, and even affect the comfort of the cockpit. In addition, most aircraft mixing chambers do not have drainage treatment, and some aircraft have simple drainage outlets, but the water removal effect is not good, and there will be bacteria breeding problems caused by the presence of condensed water in the mixing chamber. If it is brought into the cockpit by the mixed airflow It will affect the air quality in the cabin.

Contents of the invention

The object of the present invention is to provide a mixing chamber with the function of noise reduction and drainage, which is applied to the aircraft environment control system.

The technical solution of the present invention: a mixing chamber applied to an aircraft environment control system, characterized in that: the mixing chamber is provided with two sound-absorbing layers, and the sound-absorbing layer is an aluminum micro-perforated plate.

Preferably, the mixing chamber includes a premixing pipeline and a mixing chamber body, the premixing pipeline communicates with the inlet and the mixing chamber body, a spoiler is arranged in the premixing pipeline, and the spoiler divides the premixing pipeline Divide into two parts.

Preferably, the thickness of the spoiler is 1-2mm.

Preferably, the spoiler and the mixing chamber are made of aluminum.

Preferably, a drain is provided at the bottom of the mixing chamber.

Preferably, the distance between the outer shell of the mixing chamber and the outer sound-absorbing layer is 10 mm, and the distance between the outer layer of sound-absorbing layer and the inner layer of sound-absorbing layer is 20 mm.

Preferably, the diameter of the holes on the aluminum micro-perforated plate is Φ0.8mm, the perforation rates of the outer and inner sound-absorbing layers are 2% and 5% respectively, and the thickness of the sound-absorbing layers are both 0.8mm.

Preferably, the openings are distributed evenly in a staggered arrangement.

Beneficial effects of the present invention: the technical solution makes the mixing uniformity of the air temperature in the mixing chamber better in the aircraft environmental control system, can effectively reduce the airflow noise in the mixing chamber, and can effectively eliminate the condensed water formed in the mixing chamber, so that the air supply from the mixing chamber can The air quality to the cockpit and cabin is improved.

Description of drawings

Figure 1 Schematic diagram of the mixing chamber structure

Figure 2a Top view of premixing pipeline composition

Figure 2b side view of premixing pipeline composition

Figure 3 Schematic diagram of the shape of the spoiler 8

Figure 4a top view of the composition of the mixing chamber body

Figure 4b side view of the main body of the mixing chamber

Figure 5 Schematic diagram of metal support form

Figure 6 Schematic diagram of the distribution of microperforations on the anechoic layer

Figure 7 The sealing aluminum plate at the opening of the muffler layer at the inlet section of the mixing chamber body

Figure 8 The sealing aluminum plate at the opening of the sound-absorbing layer of the air supply outlet section of the cockpit of the mixing chamber body

detailed description

According to the air distribution principle in the aircraft environmental control system and the layout space restrictions on the aircraft, there are usually differences in the configuration of the mixing chamber structure and the inlet and outlet settings. In general, the typical functional inlets and outlets of the mixing room should include two cooling air supply inlets, two recirculation air supply inlets, cabin air supply outlets, and some also include ground ventilation inlets and emergency ventilation inlets. Now take a mixing chamber containing a typical functional interface as an example to describe the technical solution, but the technology of the present invention is not limited to the structural form of the mixing chamber shown in this example:

As shown in Figure 1, due to the arrangement under the floor, the arrangement space is limited, and the consideration of maintainability, the mixing chamber structure proposed by the present invention is composed of two parts, the pre-mixing pipeline 1 and the mixing chamber body 2, the spatial structure of the two The size is mainly determined in favor of temperature mixing uniformity. The pre-mixing pipeline 1 and the mixing chamber body 2 are connected by flanges through screw connections. The bolts, nuts and gasket components are not shown in the figure, and the middle is sealed with a gasket 3. Except that the gasket is made of rubber material, all other Materials of construction are all aluminum. The specific structural forms of the pre-mixing pipeline 1 and the mixing chamber body 2 are as follows:

As shown in Figure 2a and Figure 2b, the pre-mixing pipelines are composed of aluminum plates with a thickness of 1-2mm, which are left and right completely symmetrical structures, including left recirculation air supply inlet 4, right recirculation air supply inlet 5, left refrigeration supply The air inlet 6, the right refrigeration air supply inlet 7, and the outlet 9 used to connect with the inlet of the mixing chamber body. A spoiler 8 with a thickness of 1-2 mm is installed in the pre-mixing pipeline. The shape is shown in Figure 3. The pre-mixing pipeline is divided into two parts. The spoiler and the pre-mixing pipeline are welded together to completely separate the airflow on both sides and then merge at the entrance of the mixing chamber body. Simulation calculations show that the pre-mixing pipeline can make the upper four airflows mix to achieve a good pre-mixing effect, and after the airflow passes through the pre-mixing pipeline, the flow field becomes relatively regular, showing a trend of approximately symmetrical distribution relative to the spoiler .

As shown in Figure 4a and Figure 4b, the inlet and outlet of the mixing chamber body include: an inlet 10 docked with the outlet 9 of the premixing pipeline, an air supply outlet 11 for the left cabin, an air supply outlet 12 for the right cabin, an air supply outlet 13 for the cockpit, Outlet 14 with catch groove. The mixing chamber body also contains two layers of micro-perforated plate anechoic layers 15 and 16, the distance between the outer shell of the mixing chamber and the outer anechoic layer 16 is 10 mm, and the distance between the outer anechoic layer 16 and the inner anechoic layer 15 is 20 mm , in order to ensure the structural strength, metal supports can be set between the outer sound-absorbing layer 16 and the mixing chamber shell, and between the two layers of sound-absorbing layers. The structure and layout can refer to the semi-I-shaped metal support as shown in Figure 5 19, 20, the metal support and the structure at both ends can be fixed by spot welding. The specific metal support form, quantity and position are determined by the strength design requirements to meet the structural strength design requirements of each layer, and to ensure that the strength of each structural surface and the thickness of the air layer between the sound-absorbing layers are uniform.

The shell of the above-mentioned mixing chamber body is made of 1.5mm thick aluminum plate, the two layers of sound-absorbing layers are aluminum plates with a thickness of 0.8mm, the diameter of the hole on the sound-absorbing layer is Φ0.8mm, and the perforation rate of the outer layer and inner layer of sound-absorbing layer is 2 respectively. % and 5%, the distribution of openings is staggered and evenly arranged, as shown in Figure 6. The noise elimination principle of the present invention mainly uses the friction loss of the airflow in the mixing chamber in the micro-perforation on the double-layer noise elimination layer to convert the sound energy into heat energy for noise reduction. When different perforation ratios and cavity depths with different plate thicknesses are selected, the spectral performance of the muffler can be controlled so that a good noise reduction effect can be obtained within the required frequency range. Therefore, the above-mentioned parameters such as the thickness of the anechoic layer, the perforation rate, and the gap between the anechoic layers and between the anechoic layer and the mixing chamber shell are for reference only, and can be adjusted according to the actual design requirements or restrictions of different aircraft, such as noise reduction Requirements, layout space, etc., make adaptive adjustments.

It should be noted that an aluminum plate with a thickness of 1 mm is used on the openings of the double-layer anechoic layer at each inlet and outlet of the mixing chamber body, that is, between the double-layer anechoic layer, and between the outer anechoic layer and the mixing chamber shell. The aluminum plate is a cylindrical surface or a polygonal annular surface or a torus, and is sealed to prevent gas channeling, wherein: the air supply outlet 11 of the left cabin and the 12 air supply outlets of the right cabin are sealed in the form of a cylindrical surface , are directly connected with the two outlet pipelines, as shown in the partial cut-away diagram A in Figure 4a; and the inlet 10 and the cockpit air supply outlet 13 are blocked in the form of annulus, and the two corresponding annulus The structure is shown in Figure 7 and Figure 8 as a polygonal annular sealing plate 17 and an annular sealing plate 18. Pay attention to ensure the effective flow area of the airflow at each blockage, and avoid sudden changes in airflow velocity at the inlet and outlet, resulting in air vibration, so as to ensure a good noise reduction effect.

In addition, at the bottom of the mixing chamber, it is advisable to set the drain port 5 with a water collection groove at the bottom of the mixing chamber relative to the lowest point on the aircraft. Index limits are comprehensively determined, and cannot be expanded arbitrarily, otherwise it will cause excessive leakage of gas in the mixing chamber at the drain, waste the air source of the aircraft environmental control system, and affect the noise reduction effect of the anechoic layer.

The dewatering principle of the present invention is: under the comprehensive action of the cavity between the outlet 5 with the water collecting groove and the above-mentioned sound-absorbing layers 15 and 16, the condensed water and the inlet airflow formed when the airflow in the mixing chamber is mixed can be self-contained. The free water in the mixing chamber is effectively collected in the groove below the mixing chamber, and then discharged from the drain port 5, which is beneficial to the anti-corrosion of the structure of the mixing chamber, and prevents the growth of bacteria from affecting the air quality of the air supply outlet of the mixing chamber, which is beneficial to prolonging the service life of the mixing chamber , especially when used in high temperature and high humidity environment, this advantage is more significant.

All the above-mentioned inlet and outlet diameters except the drainage port 5 are set according to the airflow velocity requirements in the air distribution pipeline and the flow requirements of each outlet according to the navigation mark. The layout space on the aircraft, the principle of the environmental control system, and economy are considered and determined comprehensively, such as choosing the form of convex and concave joints + clamps.

In addition, the tiny openings on the above-mentioned double-layer anechoic layer lead to the jet flow formed by the air flow here, which is also beneficial to the uniform mixing of the temperature of the air flow in the mixing chamber body and the analysis of the water in the air flow. In order to promote water removal and protect the structure of the mixing chamber, a waterproof coating can be applied to the inner wall of the mixing chamber body shell and the inner and outer surfaces of the sound-absorbing layer.

The temperature uniformity test and noise test of the mixing chamber design technology of the present invention show that the adopted structure can well meet the temperature mixing uniformity requirements, the noise reduction effect is obvious, and the condensed water formed in the mixing chamber can be effectively discharged. In addition, since the sound-absorbing layer is set in the mixing chamber to reduce noise, it is avoided to add silencers separately in other positions of the air distribution system, which not only saves the layout space, but also facilitates the weight reduction of the system.

Claims (8)

1. A mixing chamber applied to an aircraft environment control system, characterized in that: the mixing chamber is provided with two layers of sound-absorbing layers, and the described sound-absorbing layers are aluminum micro-perforated plates. 2. A mixing chamber applied to an aircraft environment control system according to claim 1, characterized in that: the mixing chamber includes a premixing pipeline and a mixing chamber body, and the premixing pipeline and the inlet and the mixing chamber body connected, a spoiler is arranged in the premixing pipeline, and the spoiler divides the premixing pipeline into two parts. 3. A mixing chamber applied to an aircraft environment control system according to claim 2, characterized in that: the thickness of the spoiler is 1-2mm. 4. A mixing chamber applied to an aircraft environment control system according to claim 2, characterized in that: the spoiler and the mixing chamber are made of aluminum. 5. A mixing chamber applied to an aircraft environment control system according to claim 1, characterized in that: a water outlet is arranged at the bottom of the mixing chamber. 6. A kind of mixing chamber applied to the aircraft environment control system according to claim 1, characterized in that: the mixing chamber shell and the outer sound-absorbing layer are separated by 10 mm, and the outer sound-absorbing layer and the inner layer sound-absorbing layer The interval between them is 20mm. 7. A mixing chamber applied to an aircraft environment control system according to claim 1, characterized in that: the diameter of the holes on the aluminum micro-perforated plate is Φ0.8mm, and the perforation rates of the outer and inner sound-absorbing layers are respectively 2% and 5%, the thickness of the sound-absorbing layer is 0.8mm. 8. A mixing chamber applied to an aircraft environment control system according to claim 7, characterized in that: the openings are distributed in a staggered and uniform arrangement.