Length effect on entrainment limitation of vertical wickless heat pipe. (October 2016)

• Record Type: Journal Article
• Authors: Seo, Joseph; Lee, Jae-Young
• Is Part Of: International journal of heat and mass transfer. Volume 101(2016:Oct.)
• Page Start: 373
• Page End: 378
• Publication Date: 2016-10
• Subjects: Heat pipe -- Length-to-inner-diameter ratio -- Entrainment limit -- Thermosyphon -- Heat removal -- Thermal performance; Heat -- Transmission -- Periodicals; Mass transfer -- Periodicals; Chaleur -- Transmission -- Périodiques; Transfert de masse -- Périodiques; Electronic journals; 621.4022
• DOI: 10.1016/j.ijheatmasstransfer.2016.05.096
• Languages: English
• ISSNs: 0017-9310

Abstract

Highlights: The effects of the L / D ratio on the thermal hydraulics of heat pipes are examined. The effects of the L / D ratio on the entrainment limit are also considered. Various entrainment limit correlations are compared against experimental data. Discrepancies between experiment and theory are examined for various L / D values. Modifying entrainment limit correlation with L / D is conducted. Abstract: Heat pipes, which are heat transfer devices with high thermal conductance, have been studied extensively because of their applicability and efficiency. However, only a small number of studies have been conducted on relatively long heat pipes. Here, the thermal hydraulic characteristics of a long heat pipe are studied. In particular, the entrainment limit—an important design parameter—is examined to determine its sensitivity to the length-to-inner-diameter ( L / D ) ratio. Experiments are performed to measure the entrainment limits of heat pipes with various length scales. It is found that the entrainment limit points are affected by the L / D value of the heat pipe; this effect has not been considered in former correlations. Thus, a new modifying factor that includes the effect of L / D is formulated from experimental results. The correlation with the modifying factor showed good agreement with experimental results obtained in both former researches and the present study.