Pulse Combustor Pressure Gain Combustion for Gas Turbine Engine Applications

Abstract

The gas turbine engine is an integral component of the global energy infrastructure and, through widespread use, contributes significantly to the emission of harmful pollutants and greenhouse gases. As such, the research and industrial community have a significant interest in improving the thermal efficiency of these devices. However, after nearly a century of development, modern gas turbine technology is nearing its realizable efficiency limit. Thus, using conventional approaches, including increased compression ratios and turbine inlet temperatures, only small future efficiency gains are available at a high cost. If a significant increase in gas turbine engine efficiency is to be realized, a deviation from this convention is necessary. Pressure gain combustion is a new combustion technology capable of delivering a step increase in gas turbine efficiency by replacing the isobaric combustor found in conventional engines with an isochoric combustor. This modification to the engine's thermodynamic cycle enables the loss in stagnation pressure typical of an isobaric combustor to be replaced with an overall net gain in stagnation pressure across the heat addition process. In this work, a pressure gain combustion technology known as the resonant pulse combustor is studied experimentally and numerically to bridge the gap between lab-scale experiments and practical implementations. First, a functional novel active valve resonant pulse combustor was designed and prototyped, thereby demonstrating naturally aspirated resonant operation with an air inlet valve-driven at a fixed frequency. Then, a series of experimental and numerical studies were carried out to increase the pressure gain performance of the combustor, and the performance and applicability of the active valve resonant pulse combustor concept were then experimental demonstrated in atmospheric conditions with both gaseous and liquid hydrocarbon fuels. Finally, the improved active valve resonant pulse combustor's pressure gain and NOX emissions performance was characterized within a high-pressure shroud in a configuration applicable to gas turbine applications and with varied inlet pressures extending up to 3 bar. This study demonstrates the low NOX capability of the pulse combustor concept and provides insight into how the device's performance may scale with increasing inlet pressure, as would exist in a practical application.

Date of Award	May 2022
Original language	English (US)
Awarding Institution	Physical Sciences and Engineering
Supervisor	William Roberts (Supervisor)