Design method of helicopter exhaust pipe shaping spoiler

Abstract

The invention belongs to the technical field of helicopter application, and particularly relates to a design method of a helicopter exhaust pipe shaping spoiler aiming at the problems that in a gliding flight state, when wake flow acts on a vertical fin, the vertical tail pneumatic environment is unstable, oscillating transverse force is generated, and tail screening occurs. The shaping spoiler structure meets the requirement that the leeward area of the exhaust pipe is in smooth transition to the machine body or the leeward face is reduced. The method specifically comprises the following steps: S1, establishing a second-order unsteady display flow field solving model and carrying out gliding state simulation, S2, carrying out mechanism analysis, and determining the reason of tail screening, S3, determining a reference state of design scheme evaluation, S4, forming a design scheme, and S5, carrying out design scheme verification. By means of the design method, the effects of stabilizing wake flow and restraining tail screening can be achieved.

Description

technical field [0001] The invention belongs to the technical field of helicopter applications, and in particular relates to a design method for a helicopter exhaust pipe shaping spoiler. Background technique [0002] As a key part of the power cabin system, the helicopter exhaust pipe is mainly used to mix the high-temperature gas discharged from the engine with the surrounding air, thereby reducing the temperature of the exhaust gas to avoid ablation of the fuselage skin. With the gradual refinement of the technological level and theoretical analysis, the design requirements of the exhaust pipe are also gradually improved. Its shape, layout, and direction have an important impact on the exhaust efficiency, temperature, and noise. Infrared stealth has made targeted modification design research on the exhaust pipe. Since the exhaust of high-temperature gas in the power compartment will be affected by the installation position and the shape of the opening, this is directly r...

AI Technical Summary

Problems solved by technology

[0003] At present, the exhaust pipes of most models of helicopters are installed obliquely upwards at 45° on both sides of the fuselage, and protrude a part of the fuselage. However, this has a significant impact on the wake passing through the exhaust pipes.

However, in a specific downward flight state, the wake flow will act on the vertical tail, resulting in an oscillating lateral force, resulting in tail sifting that is unacceptable to the pilot.

[0004] In response to this problem, a certain type of foreign helicopter installed an airfoil at the rear of the exhaust pipe of the power cabin on the back of the fuselage to at least partially block the airflow flowing from the exhaust port of the power cabin to the tail. The aerodynamic interference wind tunnel test constantly modifies the airfoil of the power cabin, combined with aerodynamic simulation analysis technology, it is found that the installation of the airfoil can move the shedding vortex generated by the exhaust pipe and the main reducer tower to the sides of the fuselage, thereby weakening the airfoil. The adverse effect of the shedding vortex on the vertical tail has stabilized and increased the aerodynamic force of the vertical tail, but it has not completely solved the problem of tail sieving

Images