On the development of compact, high performance heat exchangers for gas turbine applications

Neal R Herring, Purdue University

Abstract

This study attempts to extend the capabilities of compact heat exchangers for usein a cooled cooling air system for aerospace gas turbines. A heat exchanger analysis showed that wire coil tube inserts were a viable means of improving the performance of a fuel-air heat exchanger. This motivated a set of experiments to characterize the heat transfer coecient of various coils with JP-10. The wire coils were shown to be a very eective means of heat transfer augmentation in the ow regime and geometry relevant to a fuel-air heat exchanger. This improvement in the heat transfer coecient led to a 44% increase in the calculated air temperature drop of a notional fuel-air heat exchanger.\nIn addition to the wire coil experiments, a series of tests were conducted to gain a better understanding of the thermo-acoustic oscillations that have been shown to occur in supercritical uids. Both pulsating and purely acoustic mode oscillations were produced. The ow conditions that produced oscillations with JP-10 in a resistively heated tube were discussed. It was found that the heat ux during pulsating type oscillations was characterized by large peaks, that were nearly twice the mean value. The oscillations data also helped to answer many questions that had been raised by the work of previous researchers. Testing with wire coil inserts showed that they did not eliminate thermo-acoustic oscillations. It was also shown that the pure acoustic mode oscillations result in approximately 30% heat transfer enhancement.

Degree

Ph.D.

Advisors

Merkle, Purdue University.

Subject Area

Aerospace engineering|Mechanical engineering

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