| Comparing with the traditional pulse combustor, the valveless self-excited pulse combustor used in this thesis save one way valve, which expands the adjustment range of the load. A decouple is set at the outlet of the tail pipe which eliminates the sound energy overflow from the outlet of the tailpipe. All of those changes lay the foundation for large-scale applications. The pulsating flow generated by the pulse combustor has high heat and mass transfer efficiency. As the important part of acoustic structure of the pulse combustor, the tailpipe has larger heat transfer area. It is necessary to learn how to take full advantage of the heat transfer area and start to do research on heat transfer characteristic of the tailpipe under the action of the pulsating flow. Curved tail pipe is widely used in engineer, now, the research on operational characteristics of pulse combustor with curved tail pipe are very little.The main contents of this paper are as follows:Get the frequency, pressure characteristics of the pulse combustor with different structures of tailpipe through through the experimental study of pulse conbustor with straight tail pipe different angles of Curved tail pipe. Determine the best tailpipe structure and working conditions with the best effect of heat transfer under the experimental conditions by comparing heat transfer intensity of the pulse combustors with different tail pipe structure. Determine the factors which affect heat transfer characteristic of the tailpipe. Determine the straight tailpipe's criteria equation of dimensionless number Nu according to the experimental data and give the application range of the equation. Dicribe heat transfer characteristic of the pulse combustor's heat transfer characteristic on the basis of the pulse combustor with straight tail pipe. The combustor's frequency gradually reduce with angle of the curved pipe increase, the pulse combustor with straight tailpipe or 45 degree curved tailpipe has the same pressure and frequency characteristic. The pulse combustor with 90 degrees curved tailpipe or 135 degree curved tailpipe has the same pressure and frequency characteristic, as the excess air coefficient and load changes the phenomenon of frequency hopping occurs. Comparing with the steady-state flow, the enhancement of heat transfer ratio of the reach 3~8; The heat transfer ratio of the pulse combustor with Straight tail pipe is weakest when the excess air ratio is less than 1.2; As the the excess air ratio larger than 1.2, the pulse combustor with 45 degree curved tailpipe has highest heat transfer Efficiency, the pulse combustor with 90 degree or 135 degree curved tailpipe has the best heat transfer efficiency at 10kw load because of the frequency hopping. |
