Surface heating effect on local heat transfer in a rotating two-pass square channel with 60 angled rib turbulators

The influence of uneven wall temperature on the local heat transfer coefficient in a rotating, two-pass, square channel with 60 ribs on the leading and trailing walls was investigated for Reynolds numbers from 2,500 to 25,000 and rotation numbers from 0 to 0.352. Each pass, composed of six isolated copper sections, had a length-to-hydraulic diameter ratio of 12. The mean rotating radius-to-hydraulic diameter ratio was 30. Three thermal boundary condition cases were studied: (A) all four walls at the same temperature, (B) all four walls at the same heat flux, and (C) trailing wall hotter than leading with side walls unheated and insulated. Results indicate that rotating ribbed wall heat transfer coefficients increase by a factor of 2 to 3 over the rotating smooth wall data and at reduced coefficient variation from inlet to exit. The heat transfer coefficients on the first pass leading wall for cases B and C are up to 70-100% higher than that for case A, while the heat transfer coefficients on the second pass trailing wall for cases B and C are up to 20-50% higher.

Surface heating effect on local heat transfer in a rotating two-pass square channel with 60 angled rib turbulators Conference Paper