Experimental and Numerical Analysis of Failure for 4-Fan Wall With Different Number of Fans Units

Fan wall is a new approach to air handler design making up of regular parallel arrangement of fans units without volute casing to replace a traditional single large fan. It is important to investigate the operation performance of fan wall for the optimal designing of fan wall central-station air handling units. In this paper, it is found with experiment that the static pressure drop for one fan unit’s failure is twice higher than that when it is off. The optimum working point in the static pressure efficiency curve is shifted to the left and the optimum efficiency is reduced by 30%. The numerical and experimental results show that when the fan fails, a lot of air will flow back to the entrance. Back flow at the entrance in the fan wall will form vortex blockage which reduces the inlet flow rate. The backflow also deteriorates the flow which will dissipate energy in the fan outlet. The research result shows that if the flow rate decreases the backflow will also decay and this finding can be employed as reference of high performance fan wall designing.