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Analysis of cylindrical heat pipes incorporating the effects of liquid-vapor coupling and non-Darcian transport. – A closed-form solution. (English) Zbl 0969.76091
The paper presents a two-dimensional anlaytical model for low-temperature cylindrical heat pipes. A closed-form solution which incorporates liquid-vapor interfacial hydrodynamic coupling and non-Darcian transport through the porous wick is obtained for predicting vapor and liquid velocity and pressure distributions. In addition, the authors obtain steady-state vapor and wall temperatures for a given input heat load in the evaporator region, and a convective boundary condition in the condenser region. The analytical model used employs matched asymptotic expansions for the liquid flow to incorporate liquid-vapor interfacial hydrodynamic coupling and boundary and inertial effects. A closed-form solution for the heat pipe capillarity limit during steady state operation is also derived. These closed-form analytical solutions provide a quick, accurate prediction method for low-temperature heat pipe operation, and are found to be in good agreement with both experimental and numerical results from the existing literature.

76T10 Liquid-gas two-phase flows, bubbly flows
76S05 Flows in porous media; filtration; seepage
80A20 Heat and mass transfer, heat flow (MSC2010)
76M45 Asymptotic methods, singular perturbations applied to problems in fluid mechanics
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