Thermal diffusion model for vapor condensation with multicomponent noncondensable gases
Author(s): HU Xuejiao, MO Xiaobao, School of Power and Mechanical Engineering, Wuhan University, Key Laboratory of Hydraulic Transients of Ministry of Education, Wuhan University
Pages: 274-278
Year: 2016 Issue: 2
Journal: Engineering Journal of Wuhan University
Keyword: condensation; heat and mass transfer; noncondensable gases; multicomponent; thermal diffusion;
Abstract: A new non-isothermal model considering the accompanied thermal diffusion across the diffusion layer is proposed.An analogy calculation for component variations in the diffusion layer in the presence of N2 and H2 was performed based on the proposed model.The mole fraction of N2 and H2in the bulk is 0.2and 0.1respectively.The results show that N2,the heavier component,accumulates close to the condensing surface and H2,the lighter component,is relatively uniformly distributed.Therefore,the heavier component may have bigger impact on vapor condensation.The variations of H2 are more obvious than N2 in the diffusion layer under different temperature gradients since the thermal diffusion factor of H2 is larger than N2.The total heat transfer coefficients of condensation with air are calculated using the proposed model and compared with experimental data.It is shown that the new model has improved agreement over the traditional diffusion layer model.
Pages: 274-278
Year: 2016 Issue: 2
Journal: Engineering Journal of Wuhan University
Keyword: condensation; heat and mass transfer; noncondensable gases; multicomponent; thermal diffusion;
Abstract: A new non-isothermal model considering the accompanied thermal diffusion across the diffusion layer is proposed.An analogy calculation for component variations in the diffusion layer in the presence of N2 and H2 was performed based on the proposed model.The mole fraction of N2 and H2in the bulk is 0.2and 0.1respectively.The results show that N2,the heavier component,accumulates close to the condensing surface and H2,the lighter component,is relatively uniformly distributed.Therefore,the heavier component may have bigger impact on vapor condensation.The variations of H2 are more obvious than N2 in the diffusion layer under different temperature gradients since the thermal diffusion factor of H2 is larger than N2.The total heat transfer coefficients of condensation with air are calculated using the proposed model and compared with experimental data.It is shown that the new model has improved agreement over the traditional diffusion layer model.
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