CRITICAL HEAT FLUX CHARACTERISTICS NEAR THE CRITICAL PRESSURE IN ROD BUNDLE COOLED BY R-134A FLUID EFFECTS OF UNHEATED RODS AND SPACER GRID
In the development of supercritical pressure water cooled reactors, it is important to understand the characteristics of a heat transfer near the thermodynamic critical point. An experimental study on the critical heat flux near the critical pressure has been performed with a 5×5 square array heater rod bundle cooled by R-134a fluid. The critical power has been accurately measured up to the reduced pressure of 0.99 (4.03MPa). The critical power decreases sharply at a pressure of about 3.8-3.9MPa as the pressure approaches the critical pressure. The CHF phenomenon near the critical pressure no longer leads to an inordinate increase in the heated wall temperature such as in the case of DNB at normal pressure conditions. In the pressure region close to the critical pressure, there is a threshold pressure at which the CHF phenomenon disappears. When the pressure exceeds the threshold pressure, the wall temperature increases monotonously without a CHF occurrence according to the power level applied to the heater rods. The effect of the unheated rods in the heater rod bundle on the critical power becomes smaller as the pressure approaches the critical pressure. The turbulence effect by the mixing vane of the spacer grid on the critical power is maintained up to a pressure of 3.95MPa.
supercritical-pressure water reactor near the critical pressure critical heat flux R-134a fluid heater rod bundle spacer grid unheated rod
Chun, S.Y. Shin, C.W. Hong, S.D. Moon, S.K. Baek, W.P.
Korea Atomic Energy Research Institute, Daejeon, Republic of Korea
国际会议
上海
英文
181-190
2007-03-12（万方平台首次上网日期，不代表论文的发表时间）