论文部分内容阅读
为了研究自然循环过冷沸腾条件下流动不稳定性和临界热流密度 ( CHF)的影响因素及其规律 ,以氟里昂作工质 ,在系统压力为 0 .9～ 2 .4MPa,入口过冷度为 -0 .61～-0 .0 8K,加热功率为 1.2～ 13 k W实验条件下 ,对自然循环过冷沸腾流动不稳定性和 CHF进行了实验研究。实验结果证实 ,自然循环系统内可能发生两类流动不稳定性 :高频声波型脉动和低频密度波型脉动。流动不稳定性的发生与整个系统的几何结构及总加热功率有关 ,而 CHF则主要取决于局部的流动参数和加热热流密度。得到了判断系统流动不稳定性的发生界限。修正的 Bowring关系式可以可靠地用于预测自然循环过冷沸腾条件下的临界热流密度
In order to study the influencing factors and regularities of flow instability and critical heat flux (CHF) under natural circulation under subcooling boiling conditions, using Freon as working medium, under the conditions of system pressure of 0.9-2.4 MPa, inlet undercooling Is -0.61-0.0.08K, and the heating power is 1.2-13kW. Experimental studies on the instability of the supercooled boiling flow and the CHF of the natural cycle are carried out. Experimental results confirm that two types of flow instabilities may occur within a natural circulation system: high frequency sonic and low frequency density wave pulsations. Flow instability occurs with the overall system geometry and total heating power, whereas CHF depends mainly on local flow parameters and heating heat flux. The threshold for judging system instability was obtained. The modified Bowring relation can be reliably used to predict the critical heat flux density under subcooled boiling conditions in natural circulation