| 摘要 |
An annular flow concentric tube heat exchanger for heating two counter flowing fluid streams has been devised. Although capable of heating gases or liquids, the primary purpose of the invention is to function as an improved recuperator for recovering exhaust heat from a Brayton Cycle gas turbine engine, Ericsson Cycle engine or similar recuperated engine. The basic element of the recuperator is a concentric tube assembly that, in the preferred embodiment, is comprised of four concentric tubes that enclose three concentric annular flow passages. The low pressure exhaust flows through the inner and outer annular passages while the high pressure compressor exit air flows through the annular passage that is between the two low pressure passages. The high and low pressure flows are in opposite directions to achieve the high effectiveness that is only available with a counterflow heat exchanger. Heat is transferred from the exhaust gas to the compressor air though the tube walls on each side of the high pressure passage. Two low pressure passages are provided for each high pressure air passage to compensate for the lower pressure (and therefore lower density) of the exhaust gas. Multiple concentric tube assemblies are used to make a recuperator. The tube assemblies terminate in header assemblies located at each end of the concentric tube assemblies. The headers are made of simple plates and rings that serve the dual function of structurally locating the concentric tube assemblies and directing the flow to the proper passage in the concentric tube assemblies. High and low pressure flow tubes provide flow passages connecting the recuperator to the engine compressor air and exhaust tubing respectively. The annular flow concentric tube recuperator can be easily made from commercial tubing with minimal special tooling and is capable of very high effectiveness with very low pressure drop.
|
