| Title |
Pool Boiling Heat Transfer Coefficients Up to Critical Heat flux on Low-fin and Turbo-B Surfaces |
| Authors |
이요한(Yohan Lee) ; 정동수(Dongsoo Jung) |
| Keywords |
핵 비등 ; 열전달계수 ; 임계 열유속 ; 낮은 핀 표면 ; Turbo-B 촉진 표면 Nucleate pool boiling ; Heat transfer coefficients ; Critical heat flux ; Low-fin surface ; Turbo-B enhanced surface |
| Abstract |
In this work, nucleate pool boiling heat transfer coefficients(HTCs) of 5 refrigerants of differing vapor pressure are measured on horizontal low fin and Turbo-B square surfaces of 9.53 mm length. Tested refrigerants are R32, R22, R134a, R152a and R245fa and HTCs are taken from 10 kW/m2 to critical heat fluxes for all refrigerant at 7℃. Wall and fluid temperatures are measured directly by thermocouples located underneath the test surface and in the liquid pool. Test results show that Critical heat fluxes(CHFs) of all enhanced surfaces are greatly improved as compared to that of a plain surface in all tested refrigerants. CHFs of all refrigerants on the 26 fpi low fin surface are increased up to 240% as compared to that of the plain surface. HTCs on both low fin and Turbo-B surfaces increase with heat flux. After certain heat flux, however, they decrease. CHFs of the Turbo-B enhanced surface are lower than that of the 26 fpi low fin surface. This phenomenon is due to the difference in surface structure of the low fin and Turbo-B surface. |