Inlet and outlet pressure losses with a cross-flow

The static pressure losses associated with fluid inlets and outlets, in a cross-flow, were studied for a number of different designs and velocity ratios, using a large duct with a pipe joining one of the walls. Air flowed through both and static pressures were measured. It is found that for an inlet the pressure loss is reduced by decreasing the angle between the pipe and the duct, and rounding the entry to the pipe on the duct wall. For the outlet pressure loss is again reduced by decreasing the angle between the duct and pipe, although there is no gain from rounding the exit junction. Overall the pressure gain at entry is less than the pressure loss at exit for a certain velocity ratio. With increasing velocity ratio the pressure loss for inlet flow decreases and becomes a pressure gain, while for outlet flow the loss increases.