Critical Heat Flux in a Forced Convective Boiling with an Impinging Jet (Effect of Subcooling)

冲击射流强制对流沸腾中的临界热通量（过冷效应）

基本信息

批准号：
03650188
负责人：
MONDE Masanori
金额：
$ 1.28万
依托单位：
Saga University
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (C)
财政年份：
1991
资助国家：
日本
起止时间：
1991 至 1992
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-03650188/
关键词：
Phase Change Critical Heat Flux Impinging Jet Subcooled Boiling Forced Convective Boiling 熱工学強制対流沸騰サブク-ル

项目摘要

Critical heat flux during forced convective boiling on a rectangular heated surface of 40 or 60 mm in length and 7 mm in width, being supplied with subcooled liquids through a small round jet which impinges at the center of the surface has been studied experimentally employing water, R113 and R22 at a pressure from 1 to 25 bar, which is raised by using N_2 gas, to obtain a high subcooling condition up to 115K. The increase in the critical heat flux due to the subcooling liquid depends on the liquid velocity, heated surface length, and the density ratio. A flow model can be proposed based on observation of the change in the flow aspect with increasing the heat flux. The following generalized correlation, which can be analytically derived by using the model, can predict about 82% of the CHF data with an accuracy of * 20%.and c_p: Specific heat of liquid, D:diameter of a disk heater, d:diameter of an impinging jet, g:gravitational acceleration, H_<fg>:latent heat of evaporation, Ja:Jakob number(=(rho_l/rho_v(C_pDELTAT_<sub>/H_<fg>), L:Length of the heated surface, q_<co>:critical heat flux for saturated boiling, q_c:critical heat flux for subcooled boiling, DELTAT_<sub>:subcooling temperature, u:velocity of a liquid jet at the nozzle exit, rho_l:density of saturated liquid,rho_v:density of saturated vapor, sigma:surface tension.

在长 40 或 60 mm、宽 7 mm 的矩形加热表面上强制对流沸腾期间的临界热通量，通过撞击表面中心的小圆形射流提供过冷液体，已使用水进行了实验研究， R113和R22在1至25 bar的压力下，通过使用N_2气体升高，以获得高达115K的高过冷条件。由于过冷液体而导致的临界热通量的增加取决于液体速度、受热表面长度和密度比。可以根据随着热通量的增加流动方面的变化的观察来提出流动模型。使用该模型可以分析得出以下广义相关性，可以预测大约 82% 的 CHF 数据，精度为 * 20%。 c_p：液体比热，D：盘式加热器直径，d：撞击射流的直径，g：重力加速度，H_<fg>：蒸发潜热，Ja：雅各布number(=(rho_l/rho_v(C_pDELTAT_<sub>/H_<fg>), L: 受热面长度, q_<co>: 饱和沸腾临界热通量, q_c: 过冷沸腾临界热通量, DELTAT_< sub>：过冷温度，u：喷嘴出口处液体射流的速度，rho_l：饱和液体密度，rho_v：饱和蒸汽密度，西格玛：表面张力。