Development of cryogenic loop heat pipes

Chandratilleke, Rohana; Hatakeyama, H.; Nakagome, Hideki

doi:10.1016/s0011-2275(97)00128-8

Cited by 36 publications

(12 citation statements)

References 9 publications

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“…For example, the most common method of heat transport in superconducting magnets is the heat conduction by a copper block. However, with the development of cryocooler-cooled superconducting magnets and large magnets applications, where the heat transport distance is large, the heat conduction by a copper block will be constrained by its cross section transport capacity [1]. In the cryobiology, vitrification of biomaterials using an ultra-high cooling rate is a way to avoid cell damage due to intracellular ice formation (IIF) and exposure to cytotoxic concentrations of solutes.…”

Section: Introductionmentioning

confidence: 99%

“…However, the investigation of cryogenic loop heat pipes and oscillating heat pipes have not been widely conducted either theoretically or experimentally. Cryogenic heat pipes reported in the literature can be categorized into four types: thermosyphons [6], wick-based heat pipes [7–9], cryogenic capillary-pumped loops [10] and cryogenic loop heat pipes [1,11,12]. These previous results [11,12] showed that the heat transport capacity of the loop heat pipe with liquid nitrogen as working fluid was very low – only 26W when it operated in a horizontal direction; and its lowest thermal resistance reached 1.3 K/W – which is too high for most of cryogenic heat transport systems.…”

Section: Introductionmentioning

confidence: 99%

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Experimental investigation of cryogenic oscillating heat pipes

Jiao¹,

Ma²,

Critser³

2009

International Journal of Heat and Mass Transfer

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A novel cryogenic heat pipe, oscillating heat pipe (OHP), which consists of an 4 × 18.5 cm evaporator, a 6 × 18.5 cm condenser, and 10 cm length of adiabatic section, has been developed and experimental characterization conducted. Experimental results show that the maximum heat transport capability of the OHP reached 380W with average temperature difference of 49 °C between the evaporator and condenser when the cryogenic OHP was charged with liquid nitrogen at 48% (v/v) and operated in a horizontal direction. The thermal resistance decreased from 0.256 to 0.112 while the heat load increased from 22.5 to 321.8 W. When the OHP was operated at a steady state and an incremental heat load was added to it, the OHP operation changed from a steady state to an unsteady state until a new steady state was reached. This process can be divided into three regions: (I) unsteady state; (II) transient state; and (III) new steady state. In the steady state, the amplitude of temperature change in the evaporator is smaller than that of the condenser while the temperature response keeps the same frequency both in the evaporator and the condenser. The experimental results also showed that the amplitude of temperature difference between the evaporator and the condenser decreased when the heat load increased.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Experimental investigation of cryogenic oscillating heat pipes

Jiao¹,

Ma²,

Critser³

2009

International Journal of Heat and Mass Transfer

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“…In general, loop heat pipes differ from conventional heat pipes in the following manner: (1) LHP's are arranged in a loop. (2) Wick complexity is only in the evaporator. (3) Vapor and liquid flow is in the same direction.…”

Section: Introductionmentioning

confidence: 99%

“…Choosing the working fluid depends upon the application and the design limitations. Chandratilleke et al [2] investigated four different working fluids trying to develop loop heat pipes that can work in the cryogenic temperature range of 4 to 77 K. Also, Chandratilleke et a1 [2] showed that loop heat pipes were able to transport ;at least 10 times the amount of heat as compared to a solid copper rod of the same size. A diameter optimization was presented by Hoke et al [3] for a micro coherent porous silicon wick using water as the working fluid.…”

Section: Introductionmentioning

confidence: 99%

Loop heat pipe (LHP) development by utilizing coherent porous silicon (CPS) wicks

Hamdan

Cytrynowicz²,

Medis³

et al.

ITherm 2002. Eighth Intersociety Conference on Thermal and Thermomechanical Phenomena in Electronic Systems (Cat. No.02CH37258)

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This paper introduces a theoretical model for a Loop Heat Pipe (LHP) utilizing a coherent porous silicon (CPS) wick. The paper investigates the effects of different parameters on the performance of the LHP such as evaporator temperature, condenser temperature, total mass charge, wick thickness, porosity, and pore size. A LHP is a two-phase device with extremely high effective thermal conductivity that uses capillary forces developed inside its wicked evaporator to pump a working fluid through a closed loop. The loop heat pipe is developed to efficiently transport heat that is generated by a highly localized concentrated heat source and then to discharge this heat to a convenient sink. This device is urgently needed to cool electronic components, especially in space applications. The LHP has been modeled utilizing the conservation equations and thermodynamic cycle. The loop heat pipe cycle is presented on a T-s diagram. A direct relation is developed between the ratio of heat going for evaporation as well as heat leaking to the compensation chamber.

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“…Chandratilleke et al [2] investigated four different working fluids trying to develop a loop beat pipe that can work in a cryogenic temperature range of 4 to 77 K. Also, Cbandratilleke et a1 [2] showed that the loop heat pipe was able to transport at least IO times the amount of heat as compared to a solid copper rod of the same size. A diameter optimization was presented by Holke et al 131 for a micro coherent porous silicon wick using water as the working fluid.…”

mentioning

confidence: 99%

Steady state model of a loop heat pipe (LHP) with coherent porous silicon (CPS) wick in the evaporator

Hamdan

Gerner

Henderson

Ninteenth Annual IEEE Semiconductor Thermal Measurement and Management Symposium, 2003.

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A theoretical study is conducted to explore the effect of different parameters on the performance of a Loop Heat Pipe (LHP). These parameters are evaporator temperature, condenser temperature, total mass charge, the tube size of piping system, and pumping distance between evaporator and condenser. This paper presents a steady state model that describes the thermodynamics, heat transfer, and fluid mechanics inside an LHP. A LHP is a two-phase device with extremely high effective thermal conductivity that utilizes the thermodynamic pressure difference that developed between the evaporator and condenser to circulate a working fluid through a closed loop. The loop heat pipe efficiently transports the heat generated by a highly localized concentrated heat source and discharges this heat to a convenient smk. The steady state LHP model is described by the conservation equations, thermodynamic relations, and capillary and nucleate boiling limits. The loop heat pipe cycle is presented on a temperahre-entropy diagram. A relationship is developed to predict the ratio of the heat of evaporation to the heat leaked to the compensation chamber. This work predicts the sue of a LHP, the pumping distance, and the maximum power that can he dissipated for a fixed source temperature. Nomenclature A CPL CPS h CP hce e k L LHP m M P Q R T r V Wick cross sectional area, m2

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Development of cryogenic loop heat pipes

Cited by 36 publications

References 9 publications

Experimental investigation of cryogenic oscillating heat pipes

Experimental investigation of cryogenic oscillating heat pipes

Loop heat pipe (LHP) development by utilizing coherent porous silicon (CPS) wicks

Steady state model of a loop heat pipe (LHP) with coherent porous silicon (CPS) wick in the evaporator

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