《厦门大学学报（自然科学版）》

超临界CO2(sCO2)可作为能量转换工质用于4代堆,使用sCO2不但能提高能量转换效率,而且可以大幅缩小设备尺寸.不过,由于sCO2的物性很特殊,目前尚没有成熟的工具来模拟sCO2的流动与传热.本文使用开源计算流体力学工具OpenFOAM,经过对热物理模型的改写与编译,开发了适用于sCO2 流动与传热的专用求解器sCO2Foam.并以sCO2在进口雷诺数约为9 000的条件下,向上流过和水平流过直径为2 mm的加热圆管为例,研究管内传热与沿程摩擦压降,将模拟计算结果分别与实验数据和/或经验关联式的计算结果对比,以验证sCO2Foam的适用性.结果表明:sCO2Foam采用k-ω湍流模型模拟出的壁温分布与实验值十分吻合; 模拟计算得到的摩擦压降与经验关联式计算结果的相对误差很小.sCO2Foam具备良好的准确性、可移植性和可拓展性,可用于sCO2流动与传热问题的研究.

Supercritical carbon dioxide(sCO2)can be used as an energy conversion working fluid for the fourth-generation nuclear system to greatly improve energy conversion efficiency and reduce the size of the devices.However,there is no mature tool to simulate the flow and heat transfer of sCO2 due to its special thermo-physical properties.This study used the open-sourced tool of computational fluid dynamics,OpenFOAM,to develop a solver for sCO2 flow and heat transfer problems,i.e.,sCO2Foam,through modifying the original thermo-physical models.The numerical simulations in which sCO2 flows through the vertical/horizontal heated pipe(D=2 mm)at inlet Reynolds number of 9 000 were taken as examples to study the heat transfer and frictional pressure drop in the pipe,compare the results with both experimental data and empirical correlations as a way to verify the applicability of sCO2Foam.The results show that sCO2Foam using k-ω turbulence model can give a wall temperature distribution that corresponds well with the experiment result.The relative errors between the frictional pressure drop calculated with sCO2Foam and that from the empirical correlations are relatively small.sCO2Foam has good accuracy,portability and expansibility and it can be used to study problems of sCO2 flow and heat transfer.

引言
1 sCO₂Foam求解器的开发
2 sCO₂Foam求解器的适用性验证
3 结论

图1 8.8 MPa下CO2的热物性随温度的变化<br/>Fig.1 Variations of the thermophysical properties of CO2 with temperature at 8.8 MPa

图1 8.8 MPa下CO2的热物性随温度的变化
Fig.1 Variations of the thermophysical properties of CO2 with temperature at 8.8 MPa

图2 OpenFOAM部分原热物理类与修改后的热物理类的继承派生关系<br/>Fig.2 Inherited derivation relation of the original and modified thermo-physical classes of OpenFOAM

图2 OpenFOAM部分原热物理类与修改后的热物理类的继承派生关系
Fig.2 Inherited derivation relation of the original and modified thermo-physical classes of OpenFOAM

图3 经sCO2Foam读取、迭代运算和输出得到的sCO2热物性参数与NIST库相应数据的对比(p0=8.8 MPa)<br/>Fig.3 The comparison of the thermophysical properties of sCO2 in NIST database with those obtained after being read,

图3 经sCO2Foam读取、迭代运算和输出得到的sCO2热物性参数与NIST库相应数据的对比(p0=8.8 MPa)
Fig.3 The comparison of the thermophysical properties of sCO2 in NIST database with those obtained after being read,

图4 物理模型与坐标系统<br/>Fig.4 Physical model and coordinate system

图4 物理模型与坐标系统
Fig.4 Physical model and coordinate system

图5 模拟结果和经验关联式计算的壁温与实验数据的比较<br/>Fig.5 The comparison between the experimental data and the results obtained both by simulation and the empirical correlations

图5 模拟结果和经验关联式计算的壁温与实验数据的比较
Fig.5 The comparison between the experimental data and the results obtained both by simulation and the empirical correlations

图6 不同入口流速下,模拟计算的摩擦压降与3个经验关联式推算的摩擦压降的对比(qw =13 631 W/m2)<br/>Fig.6 Comparison of the frictional pressure drops obtained by simulation with those by the empirical correlations at different inlet velocities(qw =13 631 W/m2)

图6 不同入口流速下,模拟计算的摩擦压降与3个经验关联式推算的摩擦压降的对比(qw =13 631 W/m2)
Fig.6 Comparison of the frictional pressure drops obtained by simulation with those by the empirical correlations at different inlet velocities(qw =13 631 W/m2)

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备注

引言

1 sCO₂Foam求解器的开发

2 sCO₂Foam求解器的适用性验证

3 结论

学报简介

备注

引言

1 sCO2Foam求解器的开发

2 sCO2Foam求解器的适用性验证

3 结 论

学报简介

1 sCO₂Foam求解器的开发

2 sCO₂Foam求解器的适用性验证

3 结论