Development of a high-performance combustor for use in a greenhouse

A beating system incorporating a newly developed combustor was used to supply worm air and moisture to the control atmosphere in a greenhouse. We developed a high-performance combustor which makes use of fuel-air counter flow. In the cylindrical combustor, atomized fuel will) accompany air impacts and mixes with the counter air flow issued from the specially designed nozzle situated near the middle of the combustor, and then ignites there. The flame shape is adjusted to be thinner or wider by changing the counter airflow. The main combusting flow passes along the periphery of the inner wall of the combustor and exhausts through an annular exit port The distance between the fuel and air supply ports is very important with respect to increasing the heat transfer rate and maintaining a stable flame. We confirmed experimentally that the combustor provided an 18% reduction in fuel cost, as compared to the current fuel-air conical supply combustor. The combustor design method and an evaluation of the performance of the combustor using experimental data are presented. In addition, analysis by Computational Fluid Dynamics (CFD) revealed that the periphery wall of the combustor is heated by the high-temperature combusting flow, thereby increasing the heat transfer rate.