The determination of pipe contraction pressure loss coefficients for incompressible turbulent flow

The accurate prediction of pipe contraction presure loss is important in the design of pipe systems, such as heat exchangers, particularly when close control of the flow distribution in a network of pipes is required. The prediction of the contraction pressure loss depends heavily on experimental data. Large discrepancies in these predictions are evident in the literature. New experimental results giving pressure loss coefficients for range of Reynolds numbers of 4×104 to 2×105 and area ratios 0.13 to 0.7 are presented and compared with those of other workers and with predictions from a method that allows for velocity profile variation through the contraction. The results show a Reynolds number dependence. The effects of small-bore pipe inlet geometry on the loss coefficients are also examined.