A Numerical Study on 2-D Flow and Heat Transfer in a Natural Gas Heater

The cylinder type natural gas heater with heat transfer medium is most widely used in gas application systems. But the conventional symmetrical arrangement of heat-exchange surfaces in cylinder is not conducive to the formation of an effective heat flow field. An effective measure of rotating the symmetrical layout structure at a certain angle is put forward creatively, which can optimize the overall heat transfer effect of the heater. The combined natural convection and radiation heat transfer model for both heating and cooling surfaces in the heat-exchanging cylinder is built. The finite volume method with unstructured body-fitted grids is employed. Analyses and comparisons of the flow conditions and temperature distributions of the cylindrical natural gas heater indifferent clockwise rotation angles (10°, 20°, 30°, 35°) are carried out. With increasing of the angle, the natural convection and radiation heat transfer will be correspondingly enhanced. When the angle exceeds than 30°, however, the natural convective circulation is destroyed instead. The numerical simulation shows the best rotation angle is 20∼30°.