Heat Transfer and Total Friction Factors in the Convergent Channels with V/⋀-shaped Ribs on Two Opposite Walls

: The measurements of heat transfer and total friction factors for turbulent flows in the convergent rectangular channels with two opposite in-line ribbed walls are reported. The study has covered three different angled ribs (30 o , 45 o and 60 o ) and Reynolds number in the range of 22,000 to 75,000. The channel, composing of ten isolated copper sections in the length of test section of 1 m, has the channel convergence ratio of D ho /D hi =0.67. The results show that the ribs pointing downstream ( ⋀ -shaped) is somewhat greater than the ribs pointing upstream (V-shaped) in the dimensionless Nusselt number and total friction factors.