| 摘要 |
PURPOSE:To reduce the number of heat-transfer pipes which heat the outside air and supply the same into a combustion chamber to air at miniaturizing a preheater, by forming each heat-transfer pipe such that a plurality of small-diameter pipes are laid in a large diameter pipe having its peripheral surface provided thereon with fins. CONSTITUTION:An air preheater for a heat gas engine arranged around a combustor, for heating the outside air, is provided therein with heat transfer pipes 100 which feed and thus heater air into a combustion chamber. Each heat transfer pipe 100 is composed of a large diameter pipe 101 and a plurality of small diameter pipes 102 inserted in the former pipe 101. Further, fins 103 are formed on the outer peripheral surface of the pipe 101. With this arrangement, the outside air introduced into the heat transfer pipe 100 flows, making in contact with the inner peripheral surface of the large diameter pipe 101 and the outer peripheral surfaces of the small diameter pipes 102, resulting in increasing of the heat transfer surface. Meanwhile combustion gas makes in contact with the outer surface of the large diameter pipe 101 and the fins 103, resulting increasing of the heat transfer surface, and therefore, heats the air sufficiently, while its temperature is lowered before it is discharged. |
