方形槽内水平圆管外相变蓄热过程的数值模拟

对以水为热载体,方形槽内水平圆管外石蜡的相变蓄热过程进行了数值模拟.通过合理的分析与假设,建立数学模型及其定解条件,并利用实验数据进行验证.引入无量纲管壁温度Ste数和无量纲相变材料初温G数,分析了Ste和G数对相变材料熔化、凝固过程的影响,给出了不同Ste教的熔化过程固液相图,结果表明:Ste数对熔化和凝固过程有显著影响,与S=0.098时的熔化时间相比,Ste =0.1875时熔化时间将会缩短将近1/2,而Ste =0.277时比Ste=0.1875时熔化时间缩短了1/3.与Ste=0.0804时的熔化时间相比,Ste =0.170时凝固时间缩短1/2,而Ste =0.259时比Ste =0.170时凝固时间缩短了1/3.G数对相变过程的影响比较小,凝固时甚至可以忽略不计.

Numerical Simulation of the Phase-change Heat Storage Process in a Square Channel Outside Horizontal Round Tubes

With water serving as the fluid for heat exchange,a numerical simulation was performed of the phase-change heat storage of parafin in a square channel and outside horizontal tubes.Through a reasonable analysis and assumptions,a mathematical model and conditions for definite solutions were established and verified by the test data.With the non-dimensional tube wall temperature Ste number and non-dimensional phase-change material initial temperature G number being introduced,the influence of the Ste and G number on the melting and solidification process of the phase-change material was analyzed with a solid-liquid phase chart of the melting process at various Ste numbers being presented.The research results show that the Ste number has a remarkable influence on the melting and solidification process.The melting duration when Ste=0.1875 is shortened by almost 1/2 compared with that when Ste=0.098.That when Ste=0.277 is shortened by 1/3 compared with that when Ste=0.1875.The solidification duration when Ste=0.0804 is shortened by 1/2 compared with that when Ste=0.170.That when Ste=0.259 is shortened by 1/3 compared with that when Ste=0.170.However,G number has a relatively small influence on the phase-change process and even the solidification duration can be neglected.