Flow boiling in micro-channels is one of the most efficient methods for heat rejection in electronics, necessitating proper system design. Numerical simulations are the most suitable tool for this purpose, with most literature focusing on CHF situations, while few studies address conditions bellow it. This paper presents a parametric analysis of an evaporator with a horizontal circular micro-tube, maintaining a fixed outlet quality, using numerical simulation. The simulation employs a one-dimensional steady-state model with FC-72 as the working fluid, considering both subcooled liquid and two-phase lengths, computed using theoretical equations and correlations. The effects of inner tube diameter, heat flux, inlet pressure, and subcooling level on key evaporator design parameters are discussed in detail. Results indicate that to minimize hydraulic pumping power, fluid temperature difference, and inlet temperature are required, the evaporator should operate with the lowest heat flux (50kW∙m-2), the largest inner tube diameter (1.3mm), the highest subcooling level (30K), and the lowest inlet pressure (2bar). Under these conditions, hydraulic pumping power can be reduced by up to 86%. Furthermore, to achieve the minimum fluid temperature difference along the tube (approximately 4.9K) and avoid CHF situation, operation with the lowest subcooling level (5K) is necessary. Finally, the ratio of the heat flux to the critical heat flux, q"/CHF, increases with rising inlet pressure and subcooling level, and/or decreasing inner tube diameter. The minimum q"/CHF ratio of 43.9% was obtained at pin=2bar, q"=50kW∙m-2, D=0.9mm, and ΔTsub=5K. These findings provide insights into optimal design parameters for evaporators in micro-electronics cooling applications.
Analysis of an evaporator with single horizontal circular micro-tube using FC-72 as working fluid for electronic cooling applications
Zummo G.;Saraceno L.;
2024-01-01
Abstract
Flow boiling in micro-channels is one of the most efficient methods for heat rejection in electronics, necessitating proper system design. Numerical simulations are the most suitable tool for this purpose, with most literature focusing on CHF situations, while few studies address conditions bellow it. This paper presents a parametric analysis of an evaporator with a horizontal circular micro-tube, maintaining a fixed outlet quality, using numerical simulation. The simulation employs a one-dimensional steady-state model with FC-72 as the working fluid, considering both subcooled liquid and two-phase lengths, computed using theoretical equations and correlations. The effects of inner tube diameter, heat flux, inlet pressure, and subcooling level on key evaporator design parameters are discussed in detail. Results indicate that to minimize hydraulic pumping power, fluid temperature difference, and inlet temperature are required, the evaporator should operate with the lowest heat flux (50kW∙m-2), the largest inner tube diameter (1.3mm), the highest subcooling level (30K), and the lowest inlet pressure (2bar). Under these conditions, hydraulic pumping power can be reduced by up to 86%. Furthermore, to achieve the minimum fluid temperature difference along the tube (approximately 4.9K) and avoid CHF situation, operation with the lowest subcooling level (5K) is necessary. Finally, the ratio of the heat flux to the critical heat flux, q"/CHF, increases with rising inlet pressure and subcooling level, and/or decreasing inner tube diameter. The minimum q"/CHF ratio of 43.9% was obtained at pin=2bar, q"=50kW∙m-2, D=0.9mm, and ΔTsub=5K. These findings provide insights into optimal design parameters for evaporators in micro-electronics cooling applications.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
