Aircraft cabin pressure dynamic change calculation method

Abstract

The invention relates to the field of aviation cockpit environment control, and provides an aviation cockpit pressure dynamic change calculation method based on the aviation cockpit pressure dynamic change process by establishing mathematical calculation models of an aviation cockpit module, an air supply module, an exhaust module, an atmospheric height module and the like. Compared with a traditional calculation method, the method not only can calculate the cabin pressure and the pressure change rate in the normal flight process of the aircraft, but also can theoretically calculate the transient pressure and the pressure change rate of the cabin under the special conditions that the ventilation flow of the cabin is suddenly changed, the adjustment of a cabin pressure adjusting system fails and the like in the flight process of the aircraft. And comparing a calculation result with industrial standard requirements to judge whether component design and control logic formulation of the cabin pressure control system are reasonable or not and whether fault positioning is accurate or not. And compared with verification by developing a prototype, establishing a simulation cabin, simulating an atmosphere cabin and the like, the development period is greatly shortened, and the verification cost is reduced.

Description

Technical Field

[0001] The invention relates to the field of aviation cabin environment control, and particularly to a method for calculating dynamic changes in aircraft cabin pressure. Background Art

[0002] Cabin pressure control is one of the important parameters for aircraft cabin environment control. Its adjustment effect is closely related to cabin comfort. It not only affects human comfort, but can also cause hypoxia and even "ear pressure" phenomenon in severe cases.

[0003] Traditionally, the dynamic pressure and pressure change rate of the cabin are generally tested by experimental methods, which are not only complicated to operate, but also difficult to test in high-altitude aircraft conditions and easily interfered with, resulting in distorted test results. At the same time, the test cost is high, the test efficiency is low, and it cannot meet the forward design requirements of the cabin pressure and pressure change rate. Summary of the invention

[0004] Purpose of the Invention

[0005] A simple, effective and accurate calculation method for the dynamic cabin pressure and pressure change rate under different flight envelopes is proposed.

[0006] Technical Solution

[0007] A method for calculating the dynamic change of aircraft cabin pressure is provided. By establishing mathematical models of the atmosphere, aircraft cabin, cabin air supply and cabin exhaust, a dynamic model of cabin pressure change during aircraft flight is established. With the time axis as input, the timely cabin pressure and pressure change rate under the aircraft flight envelope are calculated, providing a basis for the cabin pressure regulation control logic.

[0008] Further, the following steps are included:

[0009] Step 1: Establish an atmospheric model based on the flight envelope.

[0010] Formulate the aircraft flight envelope, use time as input, select the aircraft climb and descent rates, and determine the aircraft's flight altitude h at different times. The calculation formula is: h=h0+v*t.

[0011] Step 2: Establish an atmospheric model under the aircraft's flight envelope. According to the aircraft's flight altitude at different times, calculate the appropriate atmospheric altitude under the aircraft's flight envelope. The calculation formula is:

[0012] Step 3: Establish a cabin pressure model. According to the aircraft cabin capacity, cabin pressure, gas quality and gas temperature parameters, make corresponding assumptions and establish a cabin pressure change model. The calculation formula is: P*V=m*r*T0

[0013] Step 4: Establish a cabin air supply model. According to the air supply flow rate of the aircraft air conditioner, the cabin starts to supply air when the air conditioner is turned on. When it lasts for a certain time t1, the air supply reaches a stable value C. The function of the cabin air supply changing with time is derived, and the mathematical model of the cabin air supply is established. The calculation formula is:

[0014]

[0015] G k =C t≥t1

[0016] Step 5: Establish a cabin exhaust model. According to the pressure difference between the inside and outside of the cabin, the leakage area, and the gas state, calculate the cumulative exhaust volume of the cabin gas in different flight envelopes and establish a cabin exhaust model. The calculation formula is:

[0017]

[0018] Step 6: Establish a dynamic change model of aircraft cabin pressure. According to the aircraft cabin air supply, exhaust, and atmospheric pressure under the aircraft flight envelope, establish a dynamic change model of aircraft cabin pressure. The calculation formula is: P c *V=(G k +G r -G p )*r*T0

[0019] Step 7: Cabin pressure calculation: Calculate the aircraft cabin pressure in real time based on the aircraft cabin dynamic change model.

[0020] Step 8: Calculate the cabin pressure change rate. Calculate the timely cabin pressure change rate based on the aircraft cabin dynamic change model.

[0021] Furthermore, according to the aircraft flight parameters and the design parameters of the cabin pressure regulation system, the modules that affect the aircraft cabin pressure and the pressure change rate are divided, such as the cabin volume, air supply volume, exhaust volume, etc.

[0022] Furthermore, after completing step 8, the method for calculating the dynamic change of cabin pressure can be verified by dynamic tests on test benches such as a ground simulated cabin and a simulated atmosphere cabin, or can be verified by onboard flight.

[0023] Furthermore, this method is used to calculate the cabin pressure and pressure change rate at each stage during the flight of the aircraft as the external environment changes, providing a theoretical basis for the rationality of the cabin pressure control logic.

[0024] Furthermore, this method is applicable to the quantitative calculation of the dynamic changes of cabin pressure and pressure change rate during the flight of the aircraft, including the numerical calculation of transient cabin pressure and pressure change rate under special circumstances such as sudden changes in air supply flow and component failures, providing theoretical support for cabin pressure control and troubleshooting.

[0025] The beneficial effects of this application are:

[0026] The above invention is convenient to calculate and produces accurate results, and can meet the requirements of the dynamic pressure and pressure change rate of the cabin under different flight envelopes of the aircraft.

[0027] The present invention is based on the dynamic change process of aircraft cabin pressure. By establishing mathematical calculation models of aircraft cabin, air supply, exhaust, atmospheric altitude and other modules, a method for calculating the dynamic change of aircraft cabin pressure is proposed. Compared with the traditional calculation method, it can not only calculate the cabin pressure and pressure change rate during the normal flight of the aircraft, but also theoretically calculate the transient pressure and pressure change rate of the cabin under special circumstances such as sudden change of cabin ventilation flow and failure of cabin pressure regulation system during the flight of the aircraft. By comparing the calculation results with the requirements of industry standards, it is judged whether the design of cabin pressure control system components and the formulation of control logic are reasonable and whether the fault location is accurate. Compared with the development of prototypes, the establishment of simulated cabins and simulated atmospheric cabins for verification greatly shortens the development cycle and reduces the verification cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 It is a schematic diagram of the structure of the present invention. DETAILED DESCRIPTION

[0029] In order to make the purpose, technical scheme and advantages of the implementation of the present invention clearer, the technical scheme in the embodiment of the present invention will be described in more detail in combination with the embodiment of the present invention. In the example, the same or similar reference numerals throughout represent the same or similar originals or elements with the same or similar functions. The described embodiments are part of the embodiments of the present invention, not all of them. The embodiments described below by reference are exemplary and intended to be used to explain the present invention, and should not be construed as limitations on the present invention. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in the field without making creative work belong to the scope of protection of the present invention. The following is a detailed description in combination with the embodiments of the present invention.

[0030] The present invention provides a method for calculating the dynamic pressure and pressure change rate of the cabin, which is simple to operate and has accurate results under any flight envelope of an aircraft.

[0031] For ease of understanding, the present invention is further described with reference to the accompanying drawings and embodiments:

[0032] Embodiment: According to the flight parameters of a small-cabin aircraft for plain takeoff shown in Table 1, a design method for the dynamic pressure and pressure change rate of the aircraft cabin is as follows:

[0033] Table 1 Aircraft flight parameters

[0034]

[0035] Step 1: According to the aircraft's climb rate, the aircraft's climb altitude changes with time h = 0 + 20 * t

[0036] Step 2: According to the aircraft's climbing altitude, the atmospheric pressure of the aircraft changes with time:

[0037]

[0038] Step 3: Based on the cabin capacity, cabin pressure, gas quality, gas temperature and other parameters, the cabin pressure satisfies P C *100=G*287*295

[0039] Step 4: According to the characteristics of the aircraft air conditioning supply, the time from the start of air supply to the maximum air supply is 1s, and the relationship between cabin air supply and time is:

[0040] G k =-1800*t 2 +2*1800*tt<1s

[0041] G k =1800t≥1s

[0042] Step 5: Based on the cabin exhaust hole diameter, the dynamic pressure P in the cabin c 、Dynamic pressure outside the cabin P h , the relationship between cabin exhaust and time:

[0043]

[0044] Step 6: Based on the cabin air supply, exhaust, and the aircraft's atmospheric environment, the cabin dynamic pressure is: P c *100=(G k -G p )*287*295

[0045] Step 7: The theoretical calculation method of the present invention is simple and has a clear geometric model, and can accurately and quickly calculate the dynamic pressure and pressure change rate of the cabin during the flight of the aircraft, covering the field of civil aircraft.

[0046] According to the high altitude takeoff flight parameters of large cabin aircraft shown in Table 1, the design method of aircraft cabin dynamic pressure and pressure change rate is as follows:

[0047] Table 1 Aircraft flight parameters

[0048]

[0049] Step 1: According to the aircraft's climb rate, the aircraft's climb altitude changes with time h = 1000 + 10*t

[0050] Step 2: According to the aircraft's climbing altitude, the atmospheric pressure of the aircraft changes with time:

[0051]

[0052] Step 3: Based on the cabin capacity, cabin pressure, gas quality, gas temperature and other parameters, the cabin pressure satisfies P C *300=G*287*295

[0053] Step 4: According to the characteristics of the aircraft air conditioning supply, the time from the start of air supply to the maximum air supply is 1s, and the relationship between cabin air supply and time is:

[0054] G k =-3000*t 2 +2*3000*tt<1s

[0055] G k =3000t≥1s

[0056] Step 5: Based on the cabin exhaust hole diameter, the dynamic pressure P in the cabin c 、Dynamic pressure outside the cabin P h , the relationship between cabin exhaust and time:

[0057]

[0058] Step 6: Based on the cabin air supply, exhaust, and the aircraft's atmospheric environment, the cabin dynamic pressure is: P c *300=(G k -G p )*287*295

[0059] Step 7: The theoretical calculation method of the present invention is simple and has a clear geometric model, and can accurately and quickly calculate the dynamic pressure and pressure change rate of the cabin during the flight of the aircraft, covering the field of civil aircraft.

[0060] It is understood by those skilled in the art that, unless otherwise defined, all terms (including technical terms and scientific terms) used herein have the same meaning as the general understanding of ordinary technicians in the field to which the present invention belongs. It should also be understood that terms such as those defined in general dictionaries should be understood to have the same meaning as in the context of the prior art, and unless defined as here, will not be interpreted with idealized or overly formal meanings. The specific implementation methods described above further describe the purpose, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above description is only a specific implementation method of the present invention and is not intended to limit the present invention. Within the spirit and principle of the present invention, any technician familiar with the profession may use the above disclosed technical content to change or modify it into an equivalent embodiment of equivalent changes for application in other fields, but any simple modification, equivalent change and modification made to the above embodiments according to the technical essence of the present invention without departing from the technical solution content of the present invention, any modification, equivalent replacement, improvement, etc., made according to the technical essence of the present invention, should be included in the protection scope of the present invention.

Claims

1. A method for calculating the dynamic change of aircraft cabin pressure, characterized in that: By establishing mathematical models of the atmosphere, aircraft cabin, cabin air supply, and cabin exhaust, a dynamic model of cabin pressure changes during aircraft flight is established. Using the time axis as input, the timely cabin pressure and pressure change rate under the aircraft flight envelope are calculated, providing a basis for the cabin pressure regulation control logic.

2. The method according to claim 1, characterized in that The steps include: Step 1: Establish an atmospheric model based on the flight envelope; Step 2: Establish the atmospheric model under the aircraft flight envelope; Step 3: Establish cabin pressure model; Step 4: Establish the cabin air supply model; Step 5: Establish the cabin exhaust model; Step 6: Establish a dynamic change model of aircraft cabin pressure; Step 7: Cabin pressure calculation; Step 8: Calculate the cabin pressure change rate.

3. The method according to claim 2, characterized in that Step 1: Establish an atmospheric model based on the flight envelope; Formulate the aircraft flight envelope, use time as input, select the aircraft climb and descent rates, and determine the aircraft's flight altitude h at different times. The calculation formula is: h=h0+v*t.

4. The method according to claim 2, characterized in that Step 2: Establish an atmospheric model under the aircraft flight envelope, and calculate the appropriate atmospheric height under the aircraft flight envelope according to the aircraft's flight altitude at different times. The calculation formula is: .

5. The method according to claim 2, characterized in that Step 3: Establish a cabin pressure model; make corresponding assumptions based on parameters such as aircraft cabin capacity, cabin pressure, gas mass and gas temperature, and establish a cabin pressure change model. The calculation formula is: P*V=m*r*T0.

6. The method according to claim 2, characterized in that Step 4: Establish a cabin air supply model; according to the aircraft air conditioning air supply flow, the cabin starts to supply air at the moment the air conditioning is turned on. When it lasts for a certain time t1, the air supply reaches a stable value C. The function of the cabin air supply changing with time is derived, and the cabin air supply mathematical model is established; the calculation formula is:

7. The method according to claim 2, characterized in that Step 5: Establish a cabin exhaust model; calculate the cumulative exhaust volume of cabin gas in different flight envelopes according to the pressure difference between the inside and outside of the cabin, the leakage area, and the gas state, and establish a cabin exhaust model; the calculation formula is:

8. The method according to claim 2, characterized in that Step 6: Establish a dynamic change model of aircraft cabin pressure; according to the aircraft cabin air supply, exhaust, and atmospheric pressure under the aircraft flight envelope, establish a dynamic change model of aircraft cabin pressure; the calculation formula is: P c *V=(G k +G r -G p )*r*T0.

9. The method according to claim 2, characterized in that Step 7: Cabin pressure calculation, calculate the aircraft cabin real-time pressure according to the aircraft cabin dynamic change model; Step 8: Cabin pressure change rate calculation, calculate the aircraft cabin real-time pressure change rate according to the aircraft cabin dynamic change model.

10. The method according to claim 9, characterized in that According to the aircraft flight parameters and the design parameters of the cabin pressure regulation system, the modules that affect the aircraft cabin pressure and the pressure change rate are divided, such as the cabin volume, air supply volume, and exhaust volume. After completing step 8, the cabin pressure dynamic change calculation method can be verified by dynamic tests on a ground simulated cabin and a simulated atmospheric cabin test bench, or by onboard flight verification.

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