论文部分内容阅读
建立了适用于温度、压力大范围变化的超临界碳氢燃料换热特性研究的一维模型,试验验证了模型的可靠性,基于该模型分析了质量流率、换热状态转换和压力等因素对超临界碳氢燃料的换热特性的影响。结果表明:4.0 MPa的低压力工况下,在超临界碳氢燃料的拟临界温度附近存在传热强化现象,而7.0 MPa的高压力工况下,该传热强化现象消失;不论质量流率的大小,4.0 MPa工况下的传热系数始终高于7.0 MPa工况下的传热系数,压力的高低在超临界碳氢燃料的汽相换热区对传热性能的影响更为显著;40kg/(m2.s)的低质量流率条件下,由液相换热区向汽相换热区的换热状态转换将导致转换区附近的传热恶化,而增大质量流率则可避免该问题的发生。
A one-dimensional model suitable for the study of the heat transfer characteristics of supercritical hydrocarbon fuels with wide range of temperature and pressure changes was established. The reliability of the model was verified by experiments. Based on the model, the mass flow rate, state transition of heat transfer and pressure On the heat transfer characteristics of supercritical hydrocarbon fuel. The results show that there exists heat transfer enhancement near the pseudo-critical temperature of supercritical hydrocarbon fuel under low pressure of 4.0 MPa, while the heat transfer enhancement disappears under high pressure of 7.0 MPa. No matter the mass flow rate The heat transfer coefficient under the condition of 4.0 MPa is always higher than the heat transfer coefficient under the condition of 7.0 MPa. The influence of the pressure on the heat transfer performance is more obvious in the vapor phase heat exchange zone of the supercritical hydrocarbon fuel. 40kg / (m2.s) under the conditions of low mass flow rate, the liquid phase heat transfer zone to the vapor phase heat transfer zone heat transfer state will lead to deterioration of heat transfer near the transition zone, and increase the mass flow rate may be Avoid this problem.