Browsing by Subject "Heat pipe modeling"

Now showing 1 - 2 of 2

Open Access
Effect of liquid-vapor interaction on the thermal performance of a flat grooved heat pipe
(Begell House Inc., 2023-03) Derebaşı, B.; Saygan, S.; Çetin, Barbaros; Dursunkaya, Z.
Flat grooved heat pipes (FGHP) are predominantly used in electronics cooling due to their ability to transfer high heat loads with small temperature differences and superior reliability. Modeling the underlying physics is challenging due to the presence of multiple simultaneous physical phenomena, including phase change, free surface, two-phase flow and heat transfer. In this study, a recently developed modeling tool H-PAT [1] is extended by including the interaction at the interface between the two phases of the FGHP's working fluid. The vapor phase is assumed to be saturated, eliminating the need to solve the energy equation for the vapor. Analytical solutions of liquid and vapor flows are used, and the steady-state energy equation is solved via a thermal resistance network to get the temperature distribution. Interface heat transfer is modeled using the fundamental findings of kinetic theory. The model is exercised to quantify the effect of vapor spacing on the thermal performance of a flat grooved heat pipe. The results show that liquid-vapor interaction on the interface enhances the evaporation performance in the micro-region, resulting in a more uniform temperature distribution.
Open Access
Fast and predictive heat pipe design and analysis toolbox: H-Pat
(Journal of Thermal Science and Technology, 2022-04-30) Saygan, Samet; Akkuş, Yiğit; Dursunkaya, Zafer; Çetin, Barbaros
For the assessment of the thermal performance of heat pipes, a wide range of modeling is available in the literature, ranging from simple capillary limit analyses to comprehensive 3D models. While simplistic models may result in less accurate predictions of heat transfer and operating temperatures, comprehensive models may be computationally expensive. In this study, a universal computational framework is developed for a fast but sufficiently accurate modeling of traditional heat pipes, and an analysis tool based on this framework, named Heat Pipe Analysis Toolbox, in short H-PAT is presented. As a diagnostic tool, H-PAT can predict the fluid flow and heat transfer from a heat pipe under varying heat inputs up to the onset of dryout. During the initial estimation of phase change rates, the solutions of particular thin film phase change models are avoided by specifying an appropriate pattern for the mass flow rate of the liquid along the heat pipe rather than using finite element/volume based methods for the computational domain. With the help of a modular structure, H-PAT can simulate heat pipes with different wick structures as long as an expression for the average liquid velocity and corresponding pressure drop can be introduced. H-PAT is also capable of analyzing heat pipes with variable cross-sections, favorable/unfavorable gravity conditions and utilizes temperature dependent thermo-physical properties at evaporator, condenser and adiabatic regions together with heat input sensitive vapor pressure. In addition, H-PAT performs the computation very fast which also makes it a perfect design tool for researchers and design engineers in the field of thermal management.