CN102937528A - Method for adjusting supercharging conversion rotation speed of aero engine - Google Patents

Abstract

The invention belongs to the technical field of an aero engine and relates to a process adjusting method for a ground test of the aero engine, in particular to a method for adjusting supercharging conversion rotation speed of the aero engine. By means of the method, repeated test runs of the engine is not required, parts of the engine are not required to be replaced, and production cost is reduced. The method is simple and convenient to operate and improves test run yield of the engine. The method includes the following steps that an ideal conversion rotation speed range of a supercharging conversion valve required by the engine is compared with current actual conversion rotation speed; if actual conversion rotation speed of the supercharging conversion valve is larger than the ideal range, the diameter of a tail nozzle of the engine is reduced through a hydraulic actuator cylinder piston rod; otherwise, the diameter of the tail nozzle of the engine is enlarged through the hydraulic actuator cylinder piston rod until the actual conversion rotation speed of the supercharging conversion valve is adjusted to the ideal conversion rotation speed range.

Description

A kind of aeromotor supercharging conversion rotation speed regulating method

Technical field

The invention belongs to the aero engine technology field, relate to a kind of technique method of adjustment of aeromotor ground run, particularly relate to a kind of aeromotor supercharging conversion rotation speed regulating method.

Background technology

During aeromotor work, the rotor high-speed rotation reaches as high as up to ten thousand rpms, and the bearing of support rotor requires very high to lubricated lubricating oil.Because rotating speed is too high, traditional contact seal modes such as leather cup can't satisfy the requirement to the sealing of lubricating oil, so the most labyrinth gas seals structures that adopt of the oil system of aeromotor.

This structure is comprised of lubricating cavity, lubricating oil exocoel, venting cavity, its principle of work is the pressure-air that utilizes engine compressor to produce, outside lubricating cavity, between lubricating cavity, form the gas of obturaging of certain pressure gradient, prevent that the lubricating oil of lubricating cavity from leaking, thereby reach the purpose of obturaging to lubricating oil.Wherein, in order to reach the balance of the pressure of obturaging, the lubricating oil exocoel is equipped with pressure regulating valve, keeps the obturage constant pressure of air of lubricating oil exocoel.

Engine when design in order to increase work efficiency, employing utilizes the supercharging changeover valve to select the mode of the suitable air feed of obturaging according to engine operating condition, contain outside when the engine intension is got gas, high rotating speed when being slow-speed of revolution work and get gas, segmentation provides the different air of obturaging to venting cavity.

In the engines ground test run, the defective problem of conversion rotating speed of supercharging changeover valve work often appears.Need the supercharging changeover valve repeatedly more reengined after generally going wrong, change the circle of obturaging and improve the supply air line sealing, but effect is all not obvious, has caused the repetition test run of engine, the front run-in period that dispatches from the factory is long, has increased production cost.

Owing to there is this problem, need the effective troubleshooting measure of research one cover, improve the test run qualification rate of engine.

Summary of the invention

For the problem that prior art exists, the invention provides a kind of aeromotor supercharging conversion rotation speed regulating method, the method does not need to make repeatedly test run of engine, renewal part, reduced production cost, and method of adjustment is simple, and is easy to operate, improved the test run qualification rate of engine.

To achieve these goals, the present invention adopts following technical scheme, and a kind of aeromotor supercharging conversion rotation speed regulating method specifically comprises the steps:

Step 1: the ideal conversion range of speeds and the present actual conversion rotating speed of the required supercharging changeover valve of engine are compared;

Step 2: if the desirable conversion of the conversion rotating ratio of the supercharging changeover valve reality range of speeds is large, then turn the engine tail nozzle diameter down by the hydraulic actuator piston rod; Otherwise, then tune up the engine tail nozzle diameter by the hydraulic actuator piston rod; Until the conversion adjustment of rotational speed of supercharging changeover valve reality is in the desirable conversion range of speeds.

The described method of the engine tail nozzle diameter being adjusted by the hydraulic actuator piston rod specifically comprises the steps:

Steps A: increase rodless cavity pressure by the test bay hydraulic system, make it greater than rod chamber pressure, make the hydraulic actuator piston rod all shift out cavity;

Step B: the insurance on the hydraulic actuator piston rod check nut of dismantling screws out check nut;

Step C: rotational hydraulic pressurized strut piston rod, thus adjust the engine tail nozzle diameter;

Step D: after adjustment is finished, precession check nut, and installation insurance.

Principle of work of the present invention:

As shown in Figure 2, can see from the structure of supercharging changeover valve that valve 11 left sides are acting on atmospheric pressure and spring force, and the right is acting on the outer pressure of containing.When engine was not worked, by-pass air duct did not have pressure, under the effect of valve 11 on the left side springs 6, was shifted to the right to the end, had closed outer culvert for gas circuit 8, had opened high-pressure air feed road 7.When engine start and since this moment by-pass air duct pressure less, outer culvert is still being closed for gas circuit 8, at this moment, by high-pressure compressor to lubricating oil fulcrum pressure charging system air feed.Along with engine speed increases, supply gas pressure and the flow of high-pressure compressor all increase, and cause lubricating cavity pressure excessive on the one hand, and the available loss of energy of engine is increased, and motor power descends.Therefore, when from outer culvert for the difference of the gas circuit 8 outer culvert pressure that enters and the atmospheric pressure that enters from atmospheric pressure mouth 10 during greater than spring force, valve 11 moves to left, and has closed high-pressure air feed road 7, has opened outer culvert for gas circuit 8.Can determine thus, depend on the pressure differential that outer culvert pressure and atmospheric pressure cause the opportunity of supercharging changeover valve conversion.

In the constant situation of the opening pressure of supercharging changeover valve, under lower conversion speed conditions, try every possible means to improve outer culvert pressure, make the difference of itself and atmospheric pressure greater than the switch condition of spring force, just reached the purpose that reduces the conversion rotating speed of supercharging changeover valve.

Be exhausted energy constant entropy (perfect condition) to the front air current flow of nozzle after supposing low-pressure turbine, then the flow by each cross section in the same pipeline is constant, namely

Wherein: A is the nozzle sectional area, and P* is stagnation pressure, and K is constant, and T* is stagnation temperature, and q (Ma) is flow function.Because air current flow is exhausted energy isoentropic process, so

Got by formula (1)

A _{Before the accent}* q (Ma _{Before the accent})=A _{Behind the accent}* q (M _{After a transfers}) (2)

Wherein, front, the rear representative adjustment of the accent nozzle sectional area front and back of footmark accent.

When dwindling nozzle diameter, i.e. A _{Behind the accent}When reducing, q (Ma then _{Behind the accent}) increase, by flow function and Mach number relation curve as can be known, as shown in Figure 3: q (Ma _{Behind the accent}) increase, then Ma _{Behind the accent}Increase, by formula (3) as can be known:

Ma=V/a (3)

Wherein: a is local velocity of sound, and V is gas velocity,

Ma _{Behind the accent}Increase, then V _{Behind the accent}Increase.

By formula (4) as can be known: $P=\frac{\mathrm{<figure-callout\; id="2"\; label="m\; V"\; filenames="HDA00002335752900011.png"\; state="\{\{state\}\}">m</figure-callout>}{V}^{}{}^2}{2}---\left(4\right)$

V _{Behind the accent}Increase, then P _{Behind the accent}Also corresponding increase, namely dwindle the nozzle sectional area after, behind the low-pressure turbine before the nozzle pressure increase, namely the outer pressure of containing increases.

So, dwindle the engine tail nozzle sectional area, can reach the purpose that increases outer culvert pressure, reduce simultaneously the conversion rotating speed of supercharging changeover valve; Otherwise, can improve the conversion rotating speed of supercharging changeover valve.

Beneficial effect of the present invention:

The present invention can reduce the engine run time, and the reduce fuel oil consumption has been saved production cost, has avoided renewal part, and method of adjustment is simple, and is easy to operate, improved the test run qualification rate of engine.

Description of drawings

Fig. 1 is the structural representation of nozzle of aircraft engine tail parts;

Fig. 2 is the structural representation of aeromotor supercharging changeover valve;

Fig. 3 is flow function and Mach number relation curve;

Among the figure, the 1--shackle, the 2--check nut, 3--hydraulic actuator piston rod, the 4--rod chamber, the 5--rodless cavity, the 6--spring, 7--high-pressure air feed road, 8--is contained outward for gas circuit, 9--outlet, 10-atmospheric pressure mouth, 11--valve.

Embodiment

The present invention is described in further detail below in conjunction with the drawings and specific embodiments.

As shown in Figure 1, a kind of aeromotor supercharging conversion rotation speed regulating method specifically comprises the steps:

Step 1: the ideal conversion range of speeds of the required supercharging changeover valve of engine is 88～90%, and actual conversion rotating speed is 94% at present, and the desirable conversion of the conversion rotating ratio of the supercharging changeover valve reality range of speeds is large;

Step 2: turn the engine tail nozzle diameter down by hydraulic actuator piston rod 3, until the conversion adjustment of rotational speed of supercharging changeover valve reality is in the desirable conversion range of speeds.

The described method of adjusting by 3 pairs of engine tail nozzle diameters of hydraulic actuator piston rod specifically comprises the steps:

Steps A: increase rodless cavity 5 pressure by the test bay hydraulic system, make it greater than rod chamber 4 pressure, all shift out cavity to realize nozzle hydraulic actuator piston rod 3;

Step B: the insurance on hydraulic actuator piston rod 3 check nuts 2 of dismantling, and with spanner check nut 2 is screwed out 3-4 circles;

Described insurance is the stainless steel steel wire of 1.8mm;

Step C: clockwise rotate hydraulic actuator piston rod 3 with spanner, hydraulic actuator piston rod 3 rotates a circle, and about nozzle reduced 19mm, and hydraulic actuator piston rod 3 does not separate with shackle 1 in rotation process;

Step D: after adjustment is finished, precession check nut 2, and installation insurance; Namely with the stainless steel steel wire check nut 2 is fixed on the hydraulic actuator piston rod 3.

Dwindle the engine tail nozzle diameter, can reduce the conversion rotating speed of supercharging changeover valve; Otherwise, can improve the conversion rotating speed of supercharging changeover valve.

Claims (2)

1. an aeromotor supercharging conversion rotation speed regulating method is characterized in that, specifically comprises the steps:

Step 1: the ideal conversion range of speeds and the present actual conversion rotating speed of the required supercharging changeover valve of engine are compared;

Step 2: if the desirable conversion of the conversion rotating ratio of the supercharging changeover valve reality range of speeds is large, then turn the engine tail nozzle diameter down by the hydraulic actuator piston rod; Otherwise, then tune up the engine tail nozzle diameter by the hydraulic actuator piston rod; Until the conversion adjustment of rotational speed of supercharging changeover valve reality is in the desirable conversion range of speeds.

2. a kind of aeromotor supercharging conversion rotation speed regulating method according to claim 1 is characterized in that the described method of the engine tail nozzle diameter being adjusted by the hydraulic actuator piston rod, specifically comprises the steps:

Steps A: increase rodless cavity pressure by the test bay hydraulic system, make it greater than rod chamber pressure, make the hydraulic actuator piston rod all shift out cavity;

Step B: the insurance on the hydraulic actuator piston rod check nut of dismantling screws out check nut;

Step C: rotational hydraulic pressurized strut piston rod, thus adjust the engine tail nozzle diameter;

Step D: after adjustment is finished, precession check nut, and installation insurance.

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