MEASUREMENT AND CALCULATION OF GUIDE VANE PERFORMANCE IN EXPANDING BENDS FOR WIND-TUNNELS

The design of guide vanes for use in expanding bends was investigated both experimentally and numerically. The primary application in mind i s the use of expanding corners in wind-tunnels for the purpose of cons tructing compact circuits with low losses. To investigate the performa nce of guide vanes in realistic situations expansion ratios between 1 and 5/3 were tested in the experiments. These were carried out in an o pen wind-tunnel specially built for the present purpose. The experimen tal results demonstrated that suitably designed guide vanes give very low losses and retained flow quality even for quite substantial expans ion ratios. For wind-tunnel applications expansion ratios around 1.3 s eem appropriate, Optimization of a guide vane design was done using a two-dimensional cascade code, Mises. A new vane optimized for an expan sion ratio of 4/3 gave a two-dimensional total pressure-loss coefficie nt as low as 0.041 for a chord Reynolds number of 200,000.