Numerical Simulation Of Hydrothermal Processes In Lake Drukshiai: 3. Wind

Experimental results on heat transfer from concave and convex surfaces of the helical (curved) channel in gas (air) flow under transient conditions are presented. The study was performed in a helical flat channel of a rectangular cross-section with relative curvature D/h = 50.2 and relative width b/h = 9.4 in the range of regime parameter. The influence of hydrodynamic transient on heat transfer from both surfaces of the helical channel was investigated under the flow rate G increase or decrease at a different rate in time (G max/G min = 2.1-2.6). It was established that transient heat transfer in helical channel depended on the character of flow rate and also convective beat flux variation, and in comparison with quasi-steady-state heat transfer it differed by up to 40% for concave and up to 25% for convex surfaces. Transient heat transfer decreased with increasing the flow rate, and it increased with decreasing it. When the influence of convective beat flux (thermal transient) was eliminated by dependencies obtained in previous work [1], hydrodynamic transient heat transfer changed additionally by about 10-20%. (author)