Discussion: “Analysis of Asymmetric Disk-Shaped and Flat-Plate Heat Pipes” (Vafai, K., Zhu, N., and Wang, W., 1995, ASME J. Heat Transfer, 117(1), pp. 209–218)

Using the in-depth integral analysis, Vafai et al. [1] presented the asymmetric vapor velocity, the vapor and liquid pressure distributions, and the vapor temperature distribution of a disk-shaped asymmetric heat pipe. Especially, nondimensionalized vapor pressure (p_v⁺) drop equation, Eq. (16) and nondimensionalized liquid pressure (p_l⁺) drop equation, Eq. (21) from Darcy's law in their paper were analytically obtained. But the solutions of nondimensionalized pressure drop equations appear to be in error. So, we can show that a recalculation of the nondimensionalized vapor and liquid pressure drop equations leads to different results as given by Eqs. (1) and (2).