Experimentally Investigated Thermo-Hydraulic Characteristics of the Loop Heat Pipe with an Open Compensation Chamber

Afanas'ev, V. N.; Недайвозов, А. В.

doi:10.7463/1116.0849572

Cited by 3 publications

(1 citation statement)

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“…Н.Э. Баумана [10,11]. КТТ состоит из испарителя, фитиля 2, конденсатора типа «змеевик» 6 и компенсационной полости 5, которые соединены между собой трубопроводами -паропроводом 3 и конденсатопроводом 4.…”

Section: экспериментальное исследованиеunclassified

Experimental Investigation of the Operation Modes of a Flat Loop Heat Pipe

Недайвозов

Afanas'ev

2019

Nauka obraz. (Mosk.)

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The paper presents the experimentally investigated operation modes of a flat loop heat pipe (LHP). The LHP is an efficient heat transfer device operating on the principle of evaporation-condensation cycle and successfully applied in space technology, including cooling heat-stressed components of electronic devices and computer equipment.We have experimentally studied how design parameters of the vapor line and its coolant flow influence on the LHP operation mode and also have determined the causes for emerging oscillatory mode of the LHP operation at low heat load. The paper depicts the experimentally measured temperatures in the LHP characteristic points and the photographs of the coolant flow in the vapor line.Based on the experimental data, we have drawn the following conclusions:A vapor-liquid coolant flow in the vapor line in the range of the heat loads under consideration has been detected. There is no superheating vapour observed.The flow regime of the vapor-liquid mixture depends on both the heat load and the vapor pipe diameter. The decrease in the internal diameter of the investigated vapor line section from 7 mm to 4 mm led to the increase of its vapor content and to the decrease of the heating surface temperature when the heat loads were above 80 W. For example, the temperature of the heating surface T1 decreased from 109.5 °С to 100 °С at a heat load of 110 W. Reducing the heat load from 80 W to 60 W leads to a change in the flow regime of the vapor-water mixture from the annular to the slug regime. Found that at low heat loads (up to 40 W), there is no LHP loop operation observed. Periodic fluctuations in the water level in the vapor line are detected. The LHP operates in thermo-syphon mode. For these heat loads, the influence of the vapor line diameter on the thermal state of the LHP is not observed.Found that at low heat loads the LHP operation mode depends only on the flow regime of the coolant in the vapor line. With the annular regime of the coolant flow in the vapor line, a stationary mode of operation of the LHP is observed. When changing the flow regime of the coolant from the annular to the slug, the LHP operation mode is changed from stationary to oscillatory.

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Section: экспериментальное исследованиеunclassified

Experimental Investigation of the Operation Modes of a Flat Loop Heat Pipe

Недайвозов

Afanas'ev

2019

Nauka obraz. (Mosk.)

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Thermal mathematical model of a two-phase circuit with mechanical pump and thermal hydraulic accumulator

Borschev

2023

PoHEI.MB

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Growing heat release in spacecraft accompanied by simultaneous increase in its amount set the task of developing thermal control systems using the two-phase boiling coolant. It accumulates heat in the form of latent vaporization heat making it possible to transfer much larger amount of heat per the coolant unit mass flow rate than at using a single-phase coolant. In addition, introduction of heat transfer at boiling allows maintaining the object temperature in almost the entire circuit close to the boiling temperature of the selected coolant. All heat transfer processes that occur, when the substance aggregation state changes, are much more intensive than with the conventional convective heat transfer; therefore, the mass of heat exchangers, fittings and control elements of the two-phase circuit would be significantly lower than their mass in a single-phase coolant circuit. Capillary or mechanical pumps should pump the coolant in two-phase systems to ensure the thermal regime. At high power, it is more advantageous to use the two-phase boiling coolant with a mechanical pump. Creation of thermal control systems based on the two-phase circuit should be preceded by elaboration of an adequate mathematical model of the two-phase boiling coolant. Mathematical model is proposed that could be used to analyze operation of the two-phase boiling coolant and calculate hydrodynamic, heat and mass transfer processes.

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Methods for controlling temperature of the instrumentation equipment using the contour heat pipe

Borschev

2023

PoHEI.MB

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The paper considers two ways of maintaining temperature of the instrumentation equipment: using the heat pipes equipped with thermoelectric cooling plate on the compensation cavity and the control valve installed at the outlet of the evaporating radiator. Since the temperature of the contour heat pipe is mainly controlled by the temperature of the compensation cavity positioned behind the evaporator, maintaining the high-precision temperature mode of this device is an urgent task for the entire spacecraft thermal regime. In the first method, the evaporating radiator is heated or cooled depending on the plate device polarity. In the second, the compensation chamber temperature could be changed using the steam supplied to the compensation cavity by a regulator installed at the outlet of the evaporator. Temperature control using a valve is due to the fact that the steam of the working fluid enters the bellows under pressure, which depends on the temperature in the evaporator. Pressure difference between steam and gas causes the bellows to contract and expand, while the valve associated with it partially closes the openings in the housing, through which the steam enters the condenser and the compensation cavity. Detailed description of these devices operation is provided, and thermal hydraulic models of the contour heat pipes equipped with these two devices are compiled.

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Experimentally Investigated Thermo-Hydraulic Characteristics of the Loop Heat Pipe with an Open Compensation Chamber

Cited by 3 publications

References 0 publications

Experimental Investigation of the Operation Modes of a Flat Loop Heat Pipe

Experimental Investigation of the Operation Modes of a Flat Loop Heat Pipe

Thermal mathematical model of a two-phase circuit with mechanical pump and thermal hydraulic accumulator

Methods for controlling temperature of the instrumentation equipment using the contour heat pipe

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