Mathematical modeling and analysis of steady state performance of a heat pipe network. (5th December 2015)

• Record Type: Journal Article
• Authors: Mahdavi, Mahboobe; Qiu, Songgang
• Is Part Of: Applied thermal engineering. Volume 91(2015:Dec.)
• Page Start: 556
• Page End: 573
• Publication Date: 2015-12-05
• Subjects: Numerical simulation -- Steady state -- Heat pipe network -- Primary heat pipe -- Secondary heat pipe -- Thermal performance; Heat engineering -- Periodicals; Heating -- Equipment and supplies -- Periodicals; Periodicals; 621.40205
• DOI: 10.1016/j.applthermaleng.2015.08.017
• Languages: English
• ISSNs: 1359-4311

Abstract

Abstract: In the current study, the thermal-fluid phenomenon inside a heat pipe network is simulated numerically. The heat pipe is specially configured to be implemented in thermal energy storage units for a concentrating solar power system. It composed of a main heat pipe and an array of secondary heat pipes. The applied thermal energy to the disc-shaped evaporator is transferred to the heat engine by the primary heat pipe. The extra heat is delivered to the phase change material through the concentric secondary heat pipes. The vapor flow leaving the adiabatic pipe section of the primary heat pipe to the disc-shaped condenser behaves similarly to the confined jet impingement. Therefore, the condensation is not uniform over the main condenser. In order to model the physical phenomenon inside the heat pipe network, a new numerical procedure was developed. The feature that makes the procedure distinguished from other available techniques is its ability to simulate non-uniform condensation of the working fluid in the condenser section. The vapor jet impingement on the condenser surface along with condensation was modeled by attaching a porous layer adjacent to the condenser wall. This porous layer acts as a wall and let the vapor flow to split out radially while it allows mass transfer through it. The effects on the pressure and temperature distributions from the heat input, portion of heat transferred to the phase change material, main condenser geometry and secondary heat pipe configurations have been investigated. The result showed that the temperature distributions of main and secondary heat pipes are greatly affected by the geometrical features. The formed recirculation zones in the main condenser region, which depend on geometrical parameters, make the performance of heat pipes convoluted. For the case with one secondary heat pipe, placing it away from the primary heat pipe provides higher temperatures at the primary and the secondary heat pipes. It also yields more uniform temperature at the main condenser. For cases with two and three secondary heat pipes, the temperature of the secondary heat pipes highly depends on the secondary heat pipes position and the ratio of heat transfer to the PCM. Highlights: A complex geometry, high-temperature heat pipe network is numerically studied. Heat pipe network composed of primary heat pipe and array of secondary heat pipes. Combined vapor jet impingement and vapor condensation are modeled. Effects of secondary heat pipes quantity and position are studied on performance. The formed vortices in the main condenser region make the performance convoluted.