ADAPTIVE VARIABLE GEOMETRY FINS FOR SURFACE COOLER
Publication Date: 2015-Apr-01
The IP.com Prior Art Database
The disclosed invention provides a technique for optimizing heat exchanger fins of surface coolers in an aircraft engine for both ground and flight conditions. The technique includes an adaptive configuration of fins in surface coolers that uses properties of a shape memory alloy. In ground idle condition of aircraft temperature of fins is higher than transition temperature of the shape memory alloy utilized for its configuration. Consequently the fins are extended. During cruise conditions temperature of the fins decreases under transition temperature of the shape memory alloy and the fins are retracted.
The present invention relates generally to surface coolers in aircraft engines and more particularly to an adaptive configuration of fins in the surface cooler of aircraft engines.
Generally, surface coolers are used as oil coolers in aircraft engines. Surface coolers in aircraft engines are designed for ground idle condition when temperature of air is higher and air speed is low. Surface coolers are overdesigned for cruise conditions when air speed is high and air temperature is low. During cruise condition, overdesigned surface coolers add extra drag to a propulsion system and therefore increase engine specific fuel consumption. Figure 1 depicts overdesigned surface coolers for an aircraft engine with extended fins configured on a surface.
A conventional technique includes surface coolers with channeled fins. The fin defines a primary heat exchange member that is configured and disposed to facilitate an exchange of heat between two fluids.
Another conventional technique includes surface cooler layer in a turbomachine that includes fins comprising of metal foam, carbon foam, or a combination thereof. The metal foam, the carbon foam or the combination thereof is configured to augment heat transfer and enhance acoustic absorption.
One other conventional technique includes a three phase fin surface cooler in a gas turbine engine. The fins extend into an air flow pathway. The fins are disposed in heat transfer communication with a separating plate and arranged with varied configurations at each of two or more sections sequentially defined along a predominant direction of air flow along the air flow pathway.
Yet another conventional technique includes a fluid-cooling device for a turbine engine propulsive unit. The cooling device includes a set of fins extending from an outer surface towards outside of the propulsion unit and oriented parallel to air flow direction when the aircraft is in flight.
However, the above mentioned conventional techniques do not include adaptive fins geometry to different duty cycle of engine which results in more fuel consumption.
It would be desirable to have an efficient technique to optimize heat exchanger fins of surface coolers in an aircraft engine for both ground and flight conditions.
BRIEF DESCRIPTION OF DRAWINGS
Figure 1 depicts overdesigned surface coolers for an aircraft engine with extended fins configured on a surface.
Figure 2 depicts extended and retracted configurations of fins at different flight cycle.
Figure 3 depicts modulation of position of fins as function of ambient temperature.
The disclosed invention provides a technique for optimizing heat exchanger fins of surface coolers in an aircraft engine for both ground and flight conditions. The technique includes an adaptive configuration of fins in surface coolers that uses properties of a shape memory alloy. Generally, shape memory alloys are base...