Effect of evaporator tilt on a loop heat pipe with non-condensable gas

Wang, Huanfa; Lin, Guiping; Shen, Xiaobin; Bai, Lizhan; Wen, Dongsheng

doi:10.1016/j.ijheatmasstransfer.2018.09.033

Cited by 28 publications

(12 citation statements)

References 25 publications

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“…The amount of the liquid driven by the surplus of the centrifugal force automatically changes to match the pressure balance equation presented in Eq. (5). When the heat load increases, the liquid mass flow rate decreases.…”

Section: Operating Principle Under Acceleration Conditionsmentioning

confidence: 99%

“…Since the pressure drop in each element of the loop is directly related to the total mass flow rate, the liquid mass flow rate entering the vapor line will naturally self-adjust to satisfy Eqs. ( 4) and (5). Additionally, the height difference between the condenser and evaporator along the acceleration direction keeps constant.…”

Section: Operation At Centrifugal Force Driven Modementioning

confidence: 99%

“…Since the widely successful applications in the aerospace industry [4][5][6], the focus and interest of LHPs have been shifted towards the terrestrial and aeronautics applications [7][8][9].…”

Section: Introductionmentioning

confidence: 99%

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Experimental and analytical study of dual compensation chamber loop heat pipe under acceleration force assisted condition

Han

Xie

Zhu

et al. 2020

International Journal of Heat and Mass Transfer

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In this article, a combined experimental and theoretical study has been conducted to investigate the operating characteristics of a dual compensation chamber loop heat pipe (DCCLHP) with ammonia as the working fluid under acceleration force conditions. The DCCLHP with nickel wick consists of a cylindrical evaporator and dual compensation chambers at both ends of evaporator. In the current study, a new DCCLHP test rig was setup which can provide the acceleration up to 11 g. Two types of loading mode were utilized for applying heat load prior to acceleration. The heat load ranges from 25 W to 300 W. Comparisons of operating performance of the DCCLHP were carried out under both gravity and acceleration conditions. A novel centrifugal force assist concept is proposed to address the observed operating behavior.Experimental results show that: (i) the acceleration effect with the proposed orientation could improve the operation performance of the DCCLHP which may operates at the centrifugal force driven mode and capillary-centrifugal force co-driven mode. The operating temperature profile at different heat loads shows "/-shape" oblique line with the increase of the acceleration; (ii) the transition heat load from centrifugal force driven mode to capillary-centrifugal force co-driven mode changes with the variation of acceleration magnitude at both loading modes; (iii) the acceleration effect on the operating temperature is remarkably significant as the heat load is less than 100 W. The operating temperature under acceleration conditions is apparently lower than that under terrestrial gravity; (iv) the coupling change of the loop pressure, vapor-liquid distribution, two-phase flow and heat transfer caused by acceleration effect leads to the unique operation performance of the DCCLHP.

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Section: Operating Principle Under Acceleration Conditionsmentioning

confidence: 99%

Section: Operation At Centrifugal Force Driven Modementioning

confidence: 99%

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Experimental and analytical study of dual compensation chamber loop heat pipe under acceleration force assisted condition

Han

Xie

Zhu

et al. 2020

International Journal of Heat and Mass Transfer

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“…In heat pipes, the shapes of the evaporator are varied, when the LHPs were first designed, the shapes of evaporators were cylindrical (Singh et al 2014;Wang et al 2019;) (see Fig. 2).…”

Section: Structure Typesmentioning

confidence: 99%

Research and Development of Loop Heat Pipe – A Review

Ji¹,

Guo²,

Xu³

2020

Frontiers in Heat and Mass Transfer

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With fast development of electronic devices, novel strategies of thermal management have been received great attention to dissipate high heat fluxes. As an efficient heat transfer device, loop heat pipe (LHP) provides ideal solution for such purpose. Even though LHP was invented nearly half-century ago, challenges still exist on its design, fabrication and operation. The objective of this paper is to present a thorough review on LHPs, paying more attention on the working principle, advantage and configuration. The review is performed in three aspects. First, the macroscopic operation characteristics such as start-up, temperature fluctuations and anti-gravity operation are described. Second, effects of various parameters or factors such as porous wick material, pore size and micro-structure on LHPs are reviewed. Third, new concept LHPs using biporous wick and wettability modification are discussed. Finally, perspective of LHPs is presented, which guides future research and development activities, from both fundamental and application point of view.

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“…However, with the evaporator-CC coupling structure, unfavorable phenomena occur and affect system operation; these phenomena include slow start-up due to the heat leak from the evaporator to the CC [12,13], increase in the operating temperature, operation failure [14,15], working fluid reverse flow and temperature fluctuation in the LHP, which affects the normal operation of the system [16,17]. During ground operation, the tilt angles of the coupling structure directly determine the vapor-liquid distribution in the coupling structure and affect the heat leak from the evaporator to the CC [18]. According to its function, the evaporator-CC structure is equivalent to a set of temperature feedback system with an extremely complex internal heat and mass transfer mechanism.…”

Section: Introductionmentioning

confidence: 99%