Feasibility of Pulse Combustion in Micro Gas Turbines

作     者：Juha Honkatukia Esa Saari Timo Knuuttila Jaakko Larjola Jari Backman Juha Honkatukia;Esa Saari;Timo Knuuttila;Jaakko Larjola;Jari Backman

作者机构：Lappeenranta University of TechnologyP.O. Box 2053851 Lappeenranta Finland T-Turbine Oy Rakentajainkuja 4 B02330 Espoo Finland 

出 版 物：《Journal of Thermal Science》 (热科学学报（英文版）)

年 卷 期：2012年第21卷第5期

页      面：466-473页

核心收录：

学科分类：080704[工学-流体机械及工程] 08[工学] 0807[工学-动力工程及工程热物理] 

基　　金：the Finnish Funding Agency for Technology and Innovation(Tekes) T-Turbine Oy AXCO-Motors Oy and Veneveist m Pauniaho Oy for supporting this work 

主　　题：Gas turbine pulse combustion micro size low Reynolds number 

摘      要：In gas turbines, a fast decrease of efficiency appears when the output decreases; the efficiency of a large gas tur-bine （20...30 MW） is in the order of 40 %, the efficiency of a 30 kW gas turbine with a recuperator is in the order of 25 %, but the efficiency of a very small gas turbine （2...6 kW） in the order of 4...6 % （or 8... 12 % with an op- timal recuperator）. This is mainly a result of the efficiency decrease in kinetic compressors, due to the Reynolds number effect. Losses in decelerating flow in a flow passage are sensitive to the Reynolds number effects. In con- trary to the compression, the efficiency of expansion in turbines is not so sensitive to the Reynolds number; very small turbines are made with rather good efficiency because the flow acceleration stabilizes the boundary layer. This study presents a system where the kinetic compressor of a gas turbine is replaced with a pulse combustor. The combustor is filled with a combustible gas mixture, ignited, and the generated high pressure gas is expanded in the turbine. The process is repeated frequently, thus producing a pulsating flow to the turbine; or almost a uni- form flow, if several parallel combustors are used and triggered a/ternately in a proper way. Almost all the com- pression work is made by the temperature increase from the combustion. This gas turbine type is investigated theoretically and its combustor also experimentally with the conclusion that in a 2 kW power size, the pulse flow gas turbine is not as attractive as expected due to the big size and weight of parallel combustors and due to the ef- ficiency being in the order of 8 % to 10 %. However, in special applications having a very low power demand, below 1000 W, this solution has better properties when compared to the conventional gas turbine and it could be worth of a more detailed investigation.