Abstract
An analytical investigation was conducted to examine and predict the capillary dryout and rewetting behaviors occurring at the evaporator section of room-temperature heat pipes during startup. The physical model is based on the displacement of a leading-edge front of a thin liquid layer flowing on finite groove uniformly heated with a constant heat flux. Numerical solutions were obtained by a fully implicit Finite Difference Method, accounting for the movement of the liquid and a known time-variable temperature boundary condition at the liquid front. The velocity and position of the liquid front were found to vary with the applied heat flux, the initial conditions, and the thermophysical properties of the working fluid. The wall temperature distribution in the dried region was also predicted. The working fluid temperature compared well with experimental results. The analysis indicated that a partial or full dryout at the evaporator section may exist for certain heat fluxes.
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