EFFECTS OF TWO 90 DEGREE OUT OF PLANE ELBOWS UPON THE FLOW DOWNSTREAM

摘要

The flow through two 90° out of plane elbows arranged to make a 90° bend was calculated for 1 and 11 pipe diameters of straight pipe between the two elbows. The fluid was natural gas operating at a Reynolds number of 7,300,000 in a 0.203 m diameter pipe. The flow field downstream of the elbows consisted of a large single vortex causing the flow to swirl as it progressed downstream. The magnitude of the vortex decreased with elbow separation and distance downstream of the last elbow. The vortex persisted past 25D downstream of the last elbow exit.