RU2826370C1 - Device for sampling air from aircraft gas turbine engines during tests at flying laboratories and high-altitude stands - Google Patents

Abstract

FIELD: test equipment.

SUBSTANCE: invention relates to air sampling. Disclosed is a device for sampling air from aircraft gas turbine engines during tests at flying laboratories and high-altitude stands, comprising a diffuser with an internal nozzle oriented in the direction of the flow of air taken from the gas turbine engine, a T-piece, electromagnetic valves powered through the switches from the control panel, samplers with built-in concentrators and a container with built-in temperature and pressure sensors, the parameters of which are transmitted to the measuring panel, where the only container in this device is not evacuated, and inside the container there is a freely moving piston due to air flow through an electromagnetic valve and a sampler on one side of the piston and air outlet when the piston moves through the solenoid valve from the container through the solenoid valve on the other side of the piston, at the ends of the reservoir there are additional unions with plugs for the preparatory movement of the piston and flushing of the reservoir, samplers are made with simultaneous arrangement of three concentrators with conical rods screwed in the shank with a ball end to provide a throttling effect.

EFFECT: invention provides reduction of dimensions of the device without deterioration of its metrological characteristics for possibility of installation on a flying laboratory and high-altitude stands.

1 cl, 2 dwg, 1 ex

Description

The invention relates to a technique for sampling air samples taken from the compressor of aircraft gas turbine engines (GTE) to study the degree of air pollution by products entering the air conditioning system (ACS) together with the air, as well as determining the composition of harmful impurities, dangerous concentrations of gases and vapors in the air in order to increase the sensitivity and accuracy of determining the assessment of the degree of air pollution.

The main source of air pollution in aircraft cabins is the carryover of lubricating oil from the front engine mounts with its subsequent complete or partial decomposition in the compressor tract of a gas turbine engine in different operating modes. A complex mixture containing vapors and aerosols of lubricating oil, vapors of hydrocarbons, acrolein, formaldehyde, phenol and other products of oil decomposition enters the aircraft cabin from the air conditioning system.

The proposed device can be used in factory and certification tests of gas turbine engines on flying laboratories (FL) for compliance with the requirements of paragraph 25.831 of NLG 25 and paragraphs 33.66 and 33.75 of NLG 33 (Aviation Rules. Part 25. Airworthiness Standards for Transport Category Aircraft NLG 25, 2022; Part 33. Airworthiness Standards for Aircraft Engines NLG 25, 2023). This type of FL testing is carried out on modern gas turbine engines in addition to bench tests, since the engine operating conditions on the bench and in real flight conditions differ greatly, which can lead to an error in assessing the oil protection of the aircraft air conditioning system from engine oil ingress.

The "Gas Turbine Engine Test Rig" is known (Patent for Utility Model of the Russian Federation No. 44820, published on March 27, 2005), which contains a device for collecting gas samples and can be used to measure the environmental characteristics of a gas turbine engine. The device for collecting gas samples contains an analyzer, samplers located at the engine outlet, and pipelines with quick-acting shut-off valves and regulating elements, the pipeline connecting the analyzer with the quick-acting shut-off valves has a heated section made in the form of a "pipe in pipe" heat exchanger, where, to set the required temperature of the sample of the collected gas, immediately before collecting the gas sample, the inlet to the analyzer is opened by the regulating element, and then it is closed by the quick-acting shut-off and regulating element, while the device is equipped with a temperature sensor connected to the recording device,

However, due to the peculiarities of the technical layout, this stand can be used primarily for the sampling of emission gases.

There are devices for sampling air from gas turbine engines in the form of a long pipeline (extending beyond the box where the gas turbine engine is tested) and devices for concentrating impurities in the form of absorption vessels or cartridges with an adsorbent, which are then used for analysis (Methodology for checking the purity of air sampled for aircraft needs, FSUE “V. Ya. Klimov Plant”, No. H28In161, 2005).

Since the air pressure and temperature release here occurs in the pipeline (this leads to the sedimentation of most of the air impurities here and, accordingly, to an analysis error), there are no special requirements for the design of the concentration devices (samplers). Such devices have been used until recently at most aircraft engine manufacturing enterprises.

The disadvantage of such devices is the sedimentation of impurities in the pipeline before the absorption cartridges, a long sampling time and the need to recharge them with a fresh portion of sorbent, which requires special preparation.

A device for sampling oil aerosols from a gas turbine engine is known, described in the US patent "Detection of oil in turbine engine bleed air" for a method for detecting oil leaks from a gas turbine engine No. 6957569 (published on 25.10.2005). In the described method, the air flow from the gas turbine engine compressor enters a metal chamber, where aerosol oil particles are counted in real mode using a spectral method. We are talking only about oil aerosol and discrete sampling is not performed. According to the Aviation Rules, we are interested in a much wider range of air pollutants, and oil is in the air both in the form of an aerosol and in the form of vapors, which are not determined at all in the present method.

The "Device for sampling air from aircraft gas turbine engines during tests on flying laboratories" is known (patent of the Russian Federation No. 2624159, published on June 30, 2017). Here, in order to reduce the dimensions, the number of parallel samples taken is reduced, which is often impossible (limited by the number of flights). Also, evacuated containers are used, the vacuum in which must be maintained for a long time during significant vibration loads (it is necessary to place it next to the running engine), which is often difficult.

The closest in technical essence to the proposed invention is the device described in MU 1.1.258-99 (introduced on 01.07.2000 by NIISU), made in the form of a system for sampling air from aviation gas turbine engines (SOP), including a diffuser, tees with nozzles, samplers with concentrators, electromagnetic valves, evacuated containers with pressure sensors, a vacuum pump and connecting tubes. Air sampled from the gas turbine engine enters the inlet of the samplers through transfer devices of minimal dimensions and only slightly reduces the temperature before entering the concentrator. After sampling, the samplers are disassembled, the concentrators are sent without disassembling for chromatographic analysis by the method of desorption of impurities in the chromatograph evaporator, after which they are again suitable for sampling without special cleaning. The disadvantage of this device is a rather bulky design (weight over 50 kg) with a large number of elements that must be rigidly fixed under flight conditions. In addition, the same containers in the SOP are serviced by different samplers, which requires the installation of a vacuum pump in the system for their periodic vacuuming, and the air from the containers themselves after sampling and pressure measurement is not analyzed, which reduces the list of components for which the sampled air can be monitored. There is also a more complex version of this device, described in the patent of the Russian Federation No. 2494366 "Complex for air sampling", published. 09/27/2013, as well as in the article "On the issues of sampling and gas chromatographic analysis of air samples during bench tests of gas turbine engines" (Chulin I.N., Methods and devices for monitoring and diagnostics of materials, products, substances and the natural environment, doi: https://doi.org/10.23670/iri.2023.128.68., 2023) with the addition of additional vacuum containers with sensors, which further weighs down the structure and increases its dimensions, and the differences are not fundamental, and therefore it is not considered here as a prototype.

The technical result, which the claimed invention is aimed at achieving, consists in reducing the dimensions of the device without deteriorating its metrological characteristics to enable installation on a flying laboratory and high-altitude stands.

In order to achieve this technical result in a device for sampling air from aircraft gas turbine engines during tests on flying laboratories, containing a diffuser with an internal nozzle oriented in the direction of the flow of air sampled from the gas turbine engine, a tee, electromagnetic valves, electromagnetic valves powered through switches from the control panel, samplers with built-in concentrators with a sorbent and a container with built-in temperature and pressure sensors, the parameters of which are transmitted to the measuring panel, the only container in this device is not evacuated, and a freely moving piston is located inside the container, i.e. air flow through the concentrators occurs not due to vacuuming, but due to the flow of air with excess pressure from the engine, driving the internal piston. Air after the sampler enters through the electromagnetic valve and the sampler on one side of the piston and the air is released when the piston moves through the electromagnetic valve from the container through the electromagnetic valve on the other side of the piston. Each sampler contains three concentrators with a sorbent, the air pumping resistance of which is adjusted on each by screwing a conical rod with a ball end into the tailpiece to ensure a throttling effect to the same values on all concentrators. Additional nozzles with plugs are made on the ends of the container for preparatory movement of the piston to the initial position (far left) with the help of a rod inserted into them and washing the container.

Fig. 1 shows a diagram of the proposed device for sampling air from aircraft gas turbine engines during tests on flying laboratories, where:

1 - diffuser,

2 - nozzle,

3 - tee,

4 - jet,

5 - sampler,

6 - concentrator with shank,

7 - conical rod with a ball end to provide a throttling effect,

8-10 - electromagnetic valves,

11 - control panel,

12 - toggle switches,

13 - capacity,

14 - piston,

15 - temperature and pressure sensors,

16 - additional fittings with plugs,

17 - measuring device,

18 and 19 - electromagnetic valves.

The proposed device comprises a diffuser 1 with an internal nozzle 2 oriented along the air flow taken from the gas turbine engine, the air from which can flow through a tee 3 with a jet 4 through a sampler 5 (there are three samplers in the device) through concentrators with a sorbent 6 and with a conical rod with a spherical end to provide a throttling effect 7 (there are three concentrators in each sampler) through electromagnetic valves 8-10, which are powered from a control panel 11 with toggle switches 12 into a container 13 made in the form of a cylinder with an internal piston 14 moving freely inside it. Temperature and pressure sensors 15 and additional fittings with plugs 16 for the initial movement of the piston to the initial state and washing the container are located on both sides of the cylinder. The sensors are connected to a measuring panel 17, on which the readings for each sensor are displayed. Air from the non-working space (where air from the sampler does not enter) is discharged to the outside through valves 18 or 19 when the piston moves. The control panel and measuring panel are located in a safe area where the operator is located.

Operation of the device.

Before the tests begin, the dynamic resistance to the air flow of concentrators 6 is adjusted using conical rods 7 screwed into them. In this case, the same air flow through all concentrators is achieved at the same pressure (usually 1.5-2.0 atm), and piston 14, with the plugs of pipes 16 open, is moved to the extreme left position by the rod inserted through the right nipple.

The device adjusted as described above is mounted in the pylon or spacer of the engine under test on the flying laboratory (or on the high-altitude stand). Air from the GTE bleed flange is constantly supplied to the diffuser 1 during engine operation and discharged overboard. Some of it is supplied through the nozzle 2 and the tee 3 to the input of the sampler 5 (to all three) and, accordingly, to the concentrators with sorbent when simultaneously switched on from the control panel 11 by the toggle switches 12 (two of the 5, connected to the corresponding normally closed electromagnetic valves). Initially, in the selected GTE operating mode, valves 8 (bleed) and 19 (dump) are switched on. Under the pressure of the bleed air after passing through the sampler and the valve inside the tank 13, piston 14 begins to move. The temperature and pressure are recorded by sensors 15 on the measuring panel 17. When the piston moves to the extreme right position, the pressure begins to increase. When it stabilizes for 5-10 seconds, the selection stops (the switches are turned off), and the sensor readings are recorded by the operator. In the next mode, similar selection is carried out by turning on valves 10 and 18, and then 9 and 19.

After the flight, the entire device except the diffuser and tee is dismantled from the aircraft or stand and sent to the laboratory. In the laboratory, the concentrators are removed from the samplers, and then, in accordance with MU 1.1.258-99, they are gas chromatographed for organic impurity content, taking into account the volumes of air samples taken reduced to normal conditions.

The absence of pre-evacuated containers in the device, whose vacuum is difficult to control and avoid unplanned sampling, and the reduction of their number to one working container significantly reduces the dimensions of the device and increases the accuracy of the measurements.

Claims (1)

A device for sampling air from aircraft gas turbine engines during testing on flying laboratories and high-altitude stands, comprising a diffuser with an internal nozzle oriented in the direction of the flow of air sampled from the gas turbine engine, a tee, electromagnetic valves fed through switches from the control panel, samplers with built-in concentrators and a container with built-in temperature and pressure sensors, the parameters of which are transmitted to the measuring panel, characterized in that the only container in this device is not evacuated, and a freely moving piston is located inside the container due to the air intake through the electromagnetic valve and the sampler on one side of the piston and the release of air when the piston moves through the electromagnetic valve from the container through the electromagnetic valve on the other side of the piston, additional fittings with plugs are made on the ends of the container for preparatory movement of the piston and washing of the container, the samplers are made with the simultaneous placement of three concentrators with conical rods screwed into the shank with with a ball end to provide a throttling effect.