Energy Generation and Sound Abatement Modifications in a Sub-scale Turbojet Test Cell

This paper presents a design and analysis of a turbine module designed to generate electricity from the exhaust of a turbojet engine within a test cell and presents a design, analysis, and assessment of modifications to diminish the high sound level produced. The motivation is to test module technology on a sub-scale to minimize cost and risk that would be experienced if testing was done initially on full-scale test cells. Demonstrating power recapture within a sub-scale test cell serves as the next step towards reducing the high energy waste, and in turn environmental and economic impacts, of large-scale jet engine test cells. Sound dampening modifications were made to the inlet and outlet including sound absorbing and perforated aluminum sheets to further reduce noise emissions. Careful consideration was taken to apply the experimental turbine module and sound dampening modifications to an existing test cell while eliminating any possible effects on the operation of the turbojet; the turbojet will function completely independent of the added turbine and panels. Preliminary estimates for power generation, created using data previously gathered from the test cell, range from 1 to 10kW for turbojet engines ranging from 22 to 71lbf; this implies power generation on the scale of megawatts for large-scale jet engines. The impact of this paper is the validation of new technology on a sub-scale level to justify and reassure risks of modifications on a full-scale level.