RU2681192C1 - Device for the selection of average for flight air samples from aircraft gas turbine engines while taking tests on flying laboratories - Google Patents

Abstract

FIELD: sampling.SUBSTANCE: invention relates to a technique for sampling air samples taken from a compressor of aviation gas turbine engines (GTE). Device for selecting the average for the flight of air samples from aircraft gas turbine engines when tested in flying laboratories contains a diffuser with one internal nozzle, oriented in the direction of flow, taken from the compressor of a gas turbine engine of air, sampler with built-in hubs, tee. Replaceable jet is installed at the nozzle exit, limiting the air flow through the air sampling line, at the exit of which a tee is installed. Sampler with a concentrator is connected to its first branch pipe, and an adjustable air discharge valve, made in the form of a cylinder with a slot closed by a spring-loaded piston, is connected to the second branch pipe, the spring of which rests on the tip of the screw moved by rotating the head inside the nut closing this valve. At the outlet of the hub in the duct mounted temperature sensor connected to the recording equipment. Duct outlet ends with an exhaust valve, made in the same way as the excess air dump valve, which controls the air pressure at the sampler outlet, while adjusting the excess air dump valves, the outlet and cross-section of the replacement jet must ensure a constant flow of bleed air, regardless of the resistance of the concentrators to pumping air.EFFECT: reducing the size of the device without deterioration of its metrological characteristics.1 cl, 2 dwg

Description

The invention relates to techniques for sampling air samples taken from the compressor of aircraft gas turbine engines (GTE) to study the degree of air pollution by products entering air conditioning system (SCR) together with air, as well as determining the composition of harmful impurities, dangerous concentrations of gases in the air and vapor, 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 cabs is the removal of lubricating oil from the front engine mounts with its subsequent complete or partial decomposition in the compressor path of a gas turbine engine (GTE) in different modes of operation. A complex mixture containing vapors and aerosols of lubricating oil, vapors of hydrocarbons, acrolein, formaldehyde, phenol and other oil decomposition products comes from the air conditioning system into the aircraft cabin. All devices used to date in flying laboratories (LL), allow only single samples to be taken at different stages of flight. Meanwhile, to carry out GTE adjustments, information is required on the total oil entrainment from the front rotor support. This information is also of interest to toxicologists, since the possibility of replacing the standardization of maximum single concentrations by average concentrations of harmful impurities per flight is currently being considered.

The proposed device can be used in factory and certification tests of gas turbine engines for compliance with the requirements of §831 AP-25, §66 and §75 AP-33 (AP-25 - Aviation Rules. Part 25. Airworthiness standards for transport category aircraft. 2008 ., AP-33 - Aviation regulations - Part 33. Airworthiness standards for aircraft engines. 2012). This type of LL test is carried out on modern gas turbine engines in addition to the bench tests, since the operating conditions of the engine on the stand and in real flight conditions are very different, which can lead to an error in evaluating the oil protection of the air conditioning system from ingress of engine oil.

A device for concentrating impurities in gases is known, comprising a tube, a layer of sorbent particles and an inert nozzle of wire spirals equipped with a heater, on the surface of which sorbent particles are located to improve the kinetics of sorption and desorption. The proposed device can improve the basic operational characteristics of concentrators with solid sorbents.

However, this device, by its technical characteristics, is not suitable for the selection and subsequent analysis of air described in MU 1.1.258-99, introduced July 1, 2000, NIISU.

The methodical instructions of MU 1.1.258-99 (introduced on July 1, 2000 NIISU) describe a device made in the form of an aircraft gas-turbine engine air sampling system (SOP), including a diffuser, tees with nozzles, samplers with concentrators, electromagnetic valves, evacuated containers with sensors pressure, vacuum pump and connecting tubes. The air taken from the gas turbine engine enters the inlet of the samplers through the transmission devices of minimum size and only slightly reduces the temperature before entering the concentrator. After sampling, the samplers are disassembled, the concentrators are disassembled for chromatographic analysis by desorption of impurities into the evaporator of the chromatograph, after which they are again suitable for sampling without special purification.

The disadvantage of this device is the rather bulky design (weight more than 50 kg) with a large number of elements that must be rigidly fixed in flight conditions. In flight conditions, it is also difficult to use, since the electromagnetic valves are located behind the samplers, and their inlet is constantly connected to the pipeline from the diffuser, which with a constant change in pressure at the inlet to the sampler (flight conditions) and in the tube between the valve and the sampler will lead to an additional pendulum pumping some non-fixed volumes of air from the gas turbine engine through the sampler concentrator. With long flights, such pollution will be very significant, because it is not possible to take samplers during flight. This distorts the results of the subsequent gas chromatographic analysis in the direction of their significant overestimation, which may be an erroneous reason for rejecting the gas turbine engine (according to §75 AP-33, exceeding the maximum permissible concentration given in the introduction of impurities in the air taken from the gas turbine engine is considered as engine failure). In addition, the same containers in the SOP serve different samplers, which requires the installation of a vacuum pump in the system for periodic evacuation, and the air of the tanks themselves after sampling and pressure measurement does not go for analysis, which reduces the list of components for which it is possible to control the sampled air. There is a more complicated version of this device, described in RF patent No. RU 2494366 C2, with the addition of additional evacuated containers with sensors, which further complicates the design and increases its dimensions, and the differences are not fundamental, and therefore, this is not considered a prototype.

The closest in technical essence to the proposed invention is the device described in the patent of the Russian Federation No. 2624159 dated 06/30/2017, "Device for sampling air from aircraft gas turbine engines when tested in a flying laboratory", and shown in Fig. 2 (prototype). The device shown in FIG. 2, selected as a prototype, contains a diffuser 1 with an internal nozzle 2, oriented by the flow of air taken from the gas turbine engine, air from which through a flat tee 3 enters the inlet of the expansion nozzle 16, then into the expansion chamber 17 of the electromagnetic valve 18, is discharged through the nozzle 4 outlet nozzles. The piston of the valve 20, which is opened by the electromagnet 19, opens up air access (sampling) into the adapter 21, which is fixed with the lock nut 22 on the valve body and supplies air through the inlet pipe to the sampler 5, which is connected to the evacuated vessel 23, at the outlet of which the vacuum a rubber hose 24 with a plug 25. However, the use of interrupting valves and external flow drivers (evacuated containers) make the design heavier.

The technical result, to which the claimed invention is directed, consists in reducing the dimensions of the device without impairing its metrological characteristics: lack of slip and observing the principle of isokinetics, for installation on a flying laboratory for the purpose of continuous sampling of an average air sample over a flight without the use of interrupting valves and external drivers flow rate (evacuated capacity and aspirator), and using its own excess air pressure taken from the gas turbine engine.

To achieve this technical result, in a device for sampling air from aircraft gas turbine engines when tested in flying laboratories, containing a diffuser with one internal nozzle oriented in the direction of flow of the air taken from the compressor of the gas turbine engine, a sampler with built-in concentrators, a tee, at the exit of a nozzle has a replaceable nozzle limiting the air flow through the air sampling line, at the outlet of which a tee is installed, to its first a sampler with a concentrator is connected to the nozzle, and an adjustable air excess valve, made in the form of a cylinder with a slot closed by a spring-loaded piston, is connected to the second nozzle, which creates a predetermined pressure in the sub-piston space, the piston spring abuts the tip of the screw, moved by rotating the head inside the nut closing this valve. At the outlet of the concentrator, a temperature sensor is installed in the duct connected to the recording equipment. The outlet of the duct ends with an exhaust valve, similar to the excess air relief valve, which regulates the pressure at the outlet of the sampler. At the same time, the adjustment of the discharge, exhaust, and cross-section valves of the interchangeable nozzle should provide a constant flow rate of the extracted air, regardless of the resistance of the concentrators to pumping air.

This eliminates the use of electromagnetic valves and evacuated containers, and therefore significantly reduces the dimensions of the device, which is especially important for flight tests of aircraft engines.

In FIG. 1 shows a diagram of the proposed device for the selection of averages for flight air samples of aircraft gas turbine engines when tested in a flying laboratory. The device contains a diffuser 1 with an internal nozzle 2. The nozzle of the diffuser is equipped with a replaceable nozzle 4 that limits the air flow through the sampling line, at the outlet of which a tee 3 is installed, a sampler with a concentrator 5 is connected to one of its nozzles, and an adjustable excess discharge valve is connected to the other nozzle air 6, consisting of a cylinder with a slot 7, closed by a spring-loaded piston 8, which creates a predetermined pressure in the sub-piston space. The spring 9 abuts against the tip of the screw 10, moved by rotating the head 11 inside the nut 12, closing this valve 6. At the outlet of the sampler, a temperature sensor 13 is installed in the duct, connected to the recording equipment 14 (KZA). The outlet of the duct from the sampler ends with an adjustable exhaust valve 15, similar to the excess air discharge valve. The operation of the device.

The device is intended for installation directly in the pylon or spacer of the test engine in a flying laboratory (LL). The air from the gas turbine exhaust flange enters the diffuser 1 and is discharged overboard or enters the air preparation system (SPV). Part of it through the nozzle 2 and the nozzle 4 enters the tee 3 and then into the sampler with the concentrator 5. The excess air is discharged through the adjustable discharge valve 6 overboard through the slot 7, which is partially or completely closed by the freely moving piston 8 by the spring 9, the compression of which is carried out by the adjustment a screw 10 with a head 11, which are moved during rotation in the nut 12 to provide the necessary back pressure to open the valve. The temperature in the part of the air leaving the sampler with the concentrator 5 is recorded by the sensor 13 and the control recording equipment (KZA) 14. The air through the adjustable exhaust valve 15, made similar to valve 6, is discharged overboard.

Prior to installation on board, adjustments are made to valves 6 and 15 and the selection of the cross section of the nozzle 4. For this, the sampler with the concentrator and exhaust nozzle 4 is connected to an adjustable source of clean air. It should provide adjustment in the range of operating pressures of the SPV (for example, from 3 to 10 atm). At the input of the assembled installation, a pressure of 10-15% is applied less than the minimum working for SPV. The air flow rate at the outlet of the exhaust valve 15 is measured. The cross section of the nozzle 4 should provide a flow rate of 15-20 times greater than the exhaust valve 15 at the minimum operating pressure of the vent. Then the entire device is assembled, the minimum operating pressure of the vent is supplied to the inlet of the nozzle 4, and the rotation of the head 11 of the screw 10 located in the valve 6, provides the discharge of excess air while maintaining the selected flow rate at the exhaust valve 15. The device with the established adjustments is mounted on LL. During the flight, the temperature at the inlet to the relief valve and the operating time of the SST are recorded. The air flow through the sampler 5 is set, knowing the flow through the exhaust valve, adjusted for the measured temperature.

Concentrators are extracted from samplers 5, and then, according to MU 1.1.258-99, their gas chromatographic analysis for the content of organic impurities is carried out taking into account the previously determined volume of air pumped through it. Such a device with a constant pre-selected air flow rate contains a minimum of components and has a minimum size, which makes it easy to mount it on LL with any engine.

Claims (1)

A device for sampling an average air flight sample from aircraft gas turbine engines when tested in flying laboratories, containing a diffuser with one internal nozzle oriented in the direction of flow of air taken from the gas turbine engine compressor, a sampler with built-in concentrators, a tee, characterized in that at the outlet a replaceable nozzle is installed from the nozzle, limiting the air flow through the air sampling line, at the outlet of which a tee is installed, to its first patron a sampler with a concentrator is connected, and an adjustable air excess valve, connected in the form of a cylinder with a slot closed by a spring-loaded piston, is connected to the second nozzle, which creates a predetermined pressure in the sub-piston space, the spring of which abuts against the screw tip, moved by rotating the head inside the nut closing this valve, at the outlet of the concentrator in the duct there is a temperature sensor connected to the recording equipment, the duct outlet ends with an exhaust valve, performed similarly to the excess air discharge valve, which regulates the pressure at the outlet of the sampler, while the adjustment of the discharge valves, the outlet and the cross-section of the interchangeable nozzle should ensure a constant flow of sampled air, regardless of the resistance of the concentrators to pumping air.

Images