Experimental Investigation On Combined Heat Loss Characteristics Of A Cylindrical Cavity With And Without Environmental Wind

An experimental study was performed to investigate the effect of tilt angle, winddirection, wind speed, the position of heating surface and the total input heat flux onheat losses of a cylindrical cavity through electrical heating method. The cavity washeated at constant heat flux for all conditions. Three cases were discussed underno-wind environment, which including only the bottom surface heated, only the sidesurface heated and both bottom and side surfaces heated. Similarly, two cases wereexamined which contain only bottom surface heated and all surfaces heated whenconsidering the wind effect on heat losses.The main results are as follows: for no-wind condition, the bottom surfacetemperatures vary within a small region, while the side surface temperatures decreasemonotonously with increasing deviation from bottom surface, meanwhile, thetemperatures on the same cross section vary regularly with the change of measuringpoint position. Comparing with radiation and conduction heat losses, the natureconvection heat loss is more affected by tilt angle. In addition, the affection is alsodependent on the position of heating surface. The nature convection heat loss Nusseltnumber decreases drastically with increasing of tile angle, while the radiation heat lossNusselt number almost keeps constant when input heat flux is fixed.Being different from the rule of surface temperatures distribution under no-windcondition, temperatures on the same cross section are unrealated to the measuring pointposition under windy condition. The heat losses are affected by both wind speed andwind direction under windy environment, which is complex and distingwished from theheat losses change with cavity inclination monotonously in no-wind condition.Furthermore, the Nusselt numbers for combined convection and radiation heat losseschange obviously with the variation of wind speed and wind direction in windyenvironment, which is different from that the Nusselt numbers for nature convectionand radiation heat losses are mainly affected by tilt angle of cavity in no-windenvironment.Besides, the correlations for nature convection heat loss and radiation heat lossNusselt numbers under no-wind condition as well as the correlations for combinedconvection heat loss and radiation heat loss Nusselt numbers under windy environment have been obtained. The uncertainties of experimental results were also presented.