Heat Transfer During Evaporation on Capillary-Grooved Structures of Heat Pipes

Abstract

A detailed mathematical model is developed that describes heat transfer through thin liquid films in the evaporator of heat pipes with capillary grooves. The model accounts for the effects of interfacial thermal resistance, disjoining pressure, and surface roughness for a given meniscus contact angle. The free surface temperature of the liquid film is determined using the extended Kelvin equation and the expression for interfacial resistance given by the kinetic theory. The numerical results obtained are compared to existing experimental data. The importance of the surface roughness and interfacial thermal resistance in predicting the heat transfer coefficient in the grooved evaporator is demonstrated.

Numerical investigation of an evaporating meniscus in a channel

“…However, this increase varies only from 2.1% for the low heat flux case to 3.6% for the high heat flux case. A similar result was reported in [12] where the augmentation of heat transfer due to convection was only 3-5% for superheats below 5 K. For case 2, the Peclet number (Pe ~ Vw/κ) is approximately 145.…”

“…In all the three cases, the minimum and temperature is recorded at the s-l-v junction near acrylic top as it is the farthest from the heat source, while the highest temperature is seen at the contact line as it is nearest to the heat source. 12 For each case, the temperature gradient is higher when the thermocapillary phenomenon is absent. This illustrates that the mixing due to thermocapillary convection tends to reduce the temperature gradient.…”

“…In the solid domains, the quartz wafer and the acrylic top, the energy equation reduces to: 2 0 T  (12) A heat flux boundary condition is applied to simulate the heat input to the quartz wafer as noted in Fig. 2b. …”

“…Khrustalev and Faghri [12] presented a detailed mathematical model that described heat transfer from an evaporating meniscus in a capillary slot with a consideration of the liquid flow.…”

The Effect of Thickness and Permeability of Wick Structure on L-Shape Heat Pipe Performance Using Different Working Fluids

“…Reviews by (Faghri 1994), (Groll et al 1998) and (Vasiliev 2005) provided detailed information on this topic. In addition, the main theoretical and numerical studies on heat pipes with capillary grooved structures were investigated by (Khrustalev and Faghri 1995a;b), (Faghri and Khrustalev 1997), (Khrustalev and Faghri 1999), (Zhang and Faghri 2001), (Jacolot et al 2008), (Do et al 2008), (Do and Jang 2010).…”