scholarly journals The flow and heat performance of tree-like network heat sink with diverging–converging channel

2021 ◽  
Vol 236 ◽  
pp. 01027
Author(s):  
Xiugen Zhu ◽  
Peng Qian ◽  
Zizhen Huang ◽  
Chengyuan Luo ◽  
Minghou Liu
Keyword(s):  
Pressure Drop ◽  
Flow Rate ◽  
Heat Sink ◽  
Heat Dissipation ◽  
Maximum Temperature ◽  
Pumping Power ◽  
Flow Recirculation ◽  
Converging Channel ◽  
Converging Angle ◽  
Good Heat

A tree-like network heat sink with diverging–converging channel is designed, and effect of flow rate, channel diverging-converging angles on the flow and heat dissipation performance of the tree-like network heat sink is analysed and compared by numerical simulation. Results show that the diverging– converging angle of 2° can reduce the pressure drop by 14% when inlet mass flow rate is 0.00499kg/s. And the maximum temperature, the temperature difference between the maximum and minimum of the heat sink increases by 0.63K and 0.92K respectively. As the diverging-converging angle increases to 4°, however, it only reduces the pressure drop by 13% and can not bring more pressure drop due to formation of flow recirculation inside the tree-like network heat sink channel. Therefore, the diverging–converging fractal micro-channel heat sink with 2° has good heat dissipation performance with obvious lower pumping power.

Characteristic Study on the Optimization of Pin-Fin Micro Heat Sink

2009 ◽  
Author(s):  
T. J. John ◽  
B. Mathew ◽  
H. Hegab
Keyword(s):  
Pressure Drop ◽  
Thermal Resistance ◽  
Flow Rate ◽  
Heat Sink ◽  
Heat Dissipation ◽  
Heat Sinks ◽  
Low Flow ◽  
Pumping Power ◽  
Flow Rates ◽  
Pin Fin

The need for dissipating heat from microsystems has increased drastically in the last decade. Several methods of heat dissipation using air and liquids have been proposed by many studies, and pin-fin micro heat sinks are one among them. Researchers have developed several effective pin-fin structures for use in heat sinks, but not much effort has been taken towards the optimization of profile and dimensions of the pin-fin. In this paper the authors studied the effect of different pin-fin shapes on the thermal resistance and pressure drop in a specific micro heat-sink. Optimization subjected to two different constraints is studied in this paper. The first optimization is subjected to constant flow rate and the second one is subjected to constant pressure drop. Both optimization processes are carried out using computer simulations generated using COVENTORWARE™. Two of the best structures from each of these optimization studies are selected and further analysis is performed for optimizing their structure dimensions such as width, height and length. A section of the total micro heat-sink is modeled for the initial optimization of the pin-fin shape. The model consists of two sections, the substrate and the fluid. Six different shapes: square, circle, rectangle, triangle, oval and rhombus were analyzed in the initial optimization study. Preliminary tests were conducted using the first model described above for a flow rate of 0.6ml/min. The non dimensional overall thermal resistance of the heat sink, and the nondimensional pumping power was calculated from the results. A figure of merit (FOM) was developed using the nondimensional thermal resistance and nondimensional pumping power for each structure with different pin-fin shapes. Smaller the value of FOM better the performance of the heat sink. The study revealed that the circle and ellipse structures have the best performance and the rectangle structure had the worst performance at low flow rates. At high flow rates rectangular and square structures have the best performance.

The Effect of Parameter Changes to the Performance of a Triangular Shape Interrupted Microchannel Heat Sink

2012 ◽  
Vol 58 (2) ◽  
Author(s):  
Fudhail Abd Munir ◽  
Mohd Irwan Mohd Azmi ◽  
Nadlene Razali ◽  
Ernie Mat Tokit
Keyword(s):  
Contact Angle ◽  
Pressure Drop ◽  
Heat Sink ◽  
Heat Dissipation ◽  
Thermal Dissipation ◽  
Working Fluid ◽  
Uniform Heat Flux ◽  
Length Width ◽  
Fluent Software ◽  
Phase Water

The effect of parameter changes on triangular shaped interrupted microchannel performance was studied by simulation using FLUENT software. The parameters that were studied are total length, and the contact angle. On the other hand, the investigated effects were pressure drop and platinum film temperature. The flow in microchannel is laminar and single phase. Water was used as the working fluid and the interrupted microchannel is made of silicon. A thin platinum film plate was deposited to provide uniform heat flux. The geometry dimension of the heat sink is 30 mm in length, width of 7 mm and the thickness of 0.525 mm. From the simulation results, it is found that the improvement on heat dissipation may be achieved by increasing the microchannel length at the expense of increase in pressure drop. In addition to that, by reducing the contact angle will result to reduction in term of pressure drop and increases the improvement thermal dissipation.

Effect of Mass Flow Rate on Dryer Room Radiator Pressure Drop and Heat Transfer

2016 ◽  
Vol 836 ◽  
pp. 102-108
Author(s):  
Mirmanto ◽  
Emmy Dyah Sulistyowati ◽  
I Ketut Okariawan
Keyword(s):  
Heat Transfer ◽  
Pressure Drop ◽  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Electrical Power ◽  
Maximum Temperature ◽  
Inlet Temperature ◽  
Mass Flow Rates ◽  
Room Model

In the rainy season, in tropical countries, to dry stuffs is difficult. Using electrical power or fossil energy is an expensive way. Therefore, it is wise to utilize heat waste. A device that can be used for this purpose is called radiator. The effect of mass flow rate on pressure drop and heat transfer for a dryer room radiator have been experimentally investigated. The room model size was 1000 mm x 1000 mm x 1000 mm made of plywood and the overall radiator dimension was 360 mm x 220 mm x 50 mm made of copper pipes with aluminium fins. Three mass flow rates were investigated namely 12.5 g/s, 14 g/s and 16.5 g/s. The water temperature at the entrance was increased gradually and then kept at 80°C. The maximum temperature reached in the dryer room was 50°C which was at the point just above the radiator. The effect of the mass flow rate on the room temperature was insignificant, while the effect on the pressure drop was significant. Moreover, the pressure drop decreased as the inlet temperature increased. In general, the radiator is recommended to be used as the heat source in a dryer room.

scholarly journals Thermal Resistance and Pressure Drop Minimization for a Micro-gap Heat Sink with Internal Micro-fins by Parametric Optimization of Operating Conditions

CFD Letters ◽  
2021 ◽  
Vol 13 (12) ◽  
pp. 100-112
Author(s):  
Shugata Ahmed ◽  
Erwin Sulaeman ◽  
Ahmad Faris Ismail ◽  
Muhammad Hasibul Hasan ◽  
Zahir Hanouf
Keyword(s):  
Heat Flux ◽  
Pressure Drop ◽  
Thermal Resistance ◽  
Void Fraction ◽  
Heat Sink ◽  
Operating Conditions ◽  
Superior Performance ◽  
Pumping Power ◽  
Two Phase ◽  
Total Thermal Resistance

In recent years, researchers are investigating several potential applications of two-phase flow in micro-gap heat sinks; electronic cooling is one of them. Further, internal micro-fins are used to enhance the heat transfer rate. However, the pressure drop penalty due to small gap height and fin surfaces is a major concern. Hence, minimization of thermal resistance and pressure drop is required. In this paper, effects of operating conditions, e.g., wall heat flux, pumping power, and inlet void fraction, on total thermal resistance and pressure drop in a micro-gap heat sink with internal micro-fins of rectangular and triangular profiles have been investigated by numerical analysis for the R-134a coolant. Furthermore, optimization of these parameters has been carried out by response surface methodology. Simulation results show that rectangular micro-fins show superior performance compared to triangular fins in reducing thermal resistance. Finally, for an optimum condition (7.1202×10-5 W pumping power, 1.2×107 Wm-2 heat flux, and 0.03 inlet void fraction), thermal resistance and pressure drop are reduced by 56.3% and 87.2%, respectively.

Diesel Active-Flow Aftertreatment Control on a Heated Flow Bench

2010 ◽  
Author(s):  
Marko Jeftic ◽  
Shui Yu ◽  
Xiang Chen ◽  
Xiaohong Xu ◽  
Meiping Wang ◽  
...  
Keyword(s):  
Pressure Drop ◽  
Substrate Temperature ◽  
Flow Rate ◽  
Particulate Filter ◽  
Maximum Temperature ◽  
Lean Nox Trap ◽  
Sudden Increase ◽  
Flow Temperature ◽  
Lean Nox ◽  
Active Flow

Empirical investigations were carried out to explore the influence of parameters such as exhaust flow temperature, exhaust flow rate, and supplemental fuel amount on diesel aftertreatment devices. A heated flow-bench system was utilized in combination with a diesel lean NOx trap (LNT) and/or a diesel particulate filter (DPF). The heated flow bench had the capability of producing stable gas temperatures and pressure drop across these aftertreatment devices. Preliminary pressure drop diagnostics were conducted with unloaded substrates meant for LNT and DPF applications. Subsequently, the DPF was loaded with varying amounts of liquid water or liquid diesel fuel and pressure drop diagnostic tests were repeated to determine if the presence of liquid substances within the substrate could be detected. With the presence of a liquid substance, the DPF exhibited relatively flat and undetectable pressure drop variation up to a critical loading level. Once this level was reached, there was a sharp and sudden increase in pressure drop. Further tests investigated the effects of exhaust flow rate and supplemental fuel amount on raising the LNT substrate temperature as required for the LNT de-NOx regeneration process. The results suggested that the maximum substrate temperature was primarily dependant on the fuel amount. Although the exhaust flow rate had very little effect on the substrate’s maximum temperature, it was significant in determining how quickly the maximum temperature was reached.

Thermal and Hydraulic Performances of Porous Microchannel Heat Sink using Nanofluids

2021 ◽  
pp. 1-32
Author(s):  
Zahir Uddin Ahmed ◽  
Md. Roni Raihan ◽  
Omidreza Ghaffari ◽  
Muhammad Ikhlaq
Keyword(s):  
Heat Transfer ◽  
Pressure Drop ◽  
Friction Factor ◽  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Heat Sink ◽  
Hydraulic Performance ◽  
Microchannel Heat Sink ◽  
Nanoparticle Concentration

Abstract Microchannel heat sink is an effective method in compact and faster heat transfer applications. This paper numerically investigates thermal and hydraulic characteristics of a porous microchannel heat sink (PMHS) using various nanofluids. The effect of porosity, inlet velocity and nanoparticle concentration on thermal-hydraulic performance is systematically examined. The result shows a significant temperature increase (40°C) of the coolant in the porous zone. The pressure drop reduces by 35% for γ = 0.32 compared to the non-porous counterpart, and this reduction of pressure significantly continues when γ further increases. The pressure drop with win is linear for PMHS with nanofluids, and the change in pressure drop is steeper for nanofluids compared to their base fluids. The average heat transfer coefficients increases about 2.5 times for PMHS, and a further increase of 6% in is predicted with the addition of nanoparticle. The average Nusselt number increases non-linearly with Re for PMHS. The friction factor reduces by 50% when γ increases from 0.32 to 0.60, and the effect of nanofluid on friction factor is insignificant beyond the mass flow rate of 0.0004 kg/s. Whilst Cu and CuO nanoparticles help to dissipate the larger amount of heat from the microchannel, Al2O3 nanoparticle appears to have a detrimental effect on heat transfer. The thermal-hydraulic performance factor strongly depends on the nanoparticles, and it slightly decreases with the mass flow rate. The increase of nanoparticle concentration, in general, enhances both h and ΔP linearly for the range considered.

Fluid Flow and Thermal Characteristics of a Microchannel Heat Sink Subject to an Impinging Air Jet

2004 ◽  
Vol 127 (7) ◽  
pp. 770-779 ◽  
Author(s):  
Seok Pil Jang ◽  
Sung Jin Kim
Keyword(s):  
Fluid Flow ◽  
Pressure Drop ◽  
Heat Sink ◽  
Thermal Characteristics ◽  
Impinging Jet ◽  
Microchannel Heat Sink ◽  
Pumping Power ◽  
Cooling Performance ◽  
Air Jet ◽  
Temperature Distributions

In the present study, fluid-flow and heat-transfer characteristics of a microchannel heat sink subject to an impinging jet are experimentally investigated. In order to evaluate the cooling performance of a microchannel heat sink subject to an impinging jet under the condition of fixed pumping power, the pressure drop across the heat sink and temperature distributions at its base are measured. Specifically, a microthermal sensor array is fabricated and used to accurately measure temperature distributions at the base of the heat sink. Based on these experimental results, a correlation for the pressure drop across a microchannel heat sink subject to an impinging jet and a correlation for its thermal resistance are suggested. In addition, it is shown that the cooling performance of an optimized microchannel heat sink subject to an impinging jet is enhanced by about 21% compared to that of the optimized microchannel heat sink with a parallel flow under the fixed-pumping-power condition.

Experimental Investigation of an Ultrathin Manifold Microchannel Heat Sink for Liquid-Cooled Chips

2010 ◽  
Vol 132 (8) ◽  
Author(s):  
W. Escher ◽  
T. Brunschwiler ◽  
B. Michel ◽  
D. Poulikakos
Keyword(s):  
Heat Transfer ◽  
Experimental Investigation ◽  
Flow Rate ◽  
Heat Sink ◽  
Volumetric Flow Rate ◽  
Maximum Temperature ◽  
Design Parameters ◽  
Cooling Power ◽  
Microchannel Heat Sink ◽  
Manifold Microchannel

We report an experimental investigation of a novel, high performance ultrathin manifold microchannel heat sink. The heat sink consists of impinging liquid slot-jets on a structured surface fed with liquid coolant by an overlying two-dimensional manifold. We developed a fabrication and packaging procedure to manufacture prototypes by means of standard microprocessing. A closed fluid loop for precise hydrodynamic and thermal characterization of six different test vehicles was built. We studied the influence of the number of manifold systems, the width of the heat transfer microchannels, the volumetric flow rate, and the pumping power on the hydrodynamic and thermal performance of the heat sink. A design with 12.5 manifold systems and 25 μm wide microchannels as the heat transfer structure provided the optimum choice of design parameters. For a volumetric flow rate of 1.3 l/min we demonstrated a total thermal resistance between the maximum heater temperature and fluid inlet temperature of 0.09 cm2 K/W with a pressure drop of 0.22 bar on a 2×2 cm2 chip. This allows for cooling power densities of more than 700 W/cm2 for a maximum temperature difference between the chip and the fluid inlet of 65 K. The total height of the heat sink did not exceed 2 mm, and includes a 500 μm thick thermal test chip structured by 300 μm deep microchannels for heat transfer. Furthermore, we discuss the influence of elevated fluid inlet temperatures, allowing possible reuse of the thermal energy, and demonstrate an enhancement of the heat sink cooling efficiency of more than 40% for a temperature rise of 50 K.

scholarly journals Thermal analysis and parametric optimization of plate fin heat sinks under forced air convection

2021 ◽  
pp. 81-81
Author(s):  
Zulfiqar Khattak ◽  
Hafiz Ali
Keyword(s):  
Pressure Drop ◽  
Thermal Resistance ◽  
Heat Sink ◽  
Heat Dissipation ◽  
Parametric Optimization ◽  
Heat Sinks ◽  
Air Velocity ◽  
Forced Air ◽  
Theoretical Results ◽  
Plate Type

Heat dissipation is becoming more and more challenging with the preface of new electronic components having staggering heat generation levels. Present day solutions should have optimized outcomes with reference to the heat sink scenarios. The experimental and theoretical results for plate type heat sink based on mathematical models have been presented in the first part of the paper. Then the parametric optimization (topology optimization) of plate type heat sink using Levenberg-Marquardt technique employed in the COMSOL Multiphysics? software is discussed. Thermal resistance of heat sink is taken as objective function against the variable length in a predefined range. Single as well as multi-parametric optimization of plate type heat sink is reported in the context of pressure drop and air velocity (Reynolds number) inside the tunnel. The results reported are compared with the numerical modeled data and experimental investigation to establish the conformity of results for applied usage. Mutual reimbursements of greater heat dissipation with minimum flow rates are confidently achievable through balanced, heat sink geometry as evident by the presented simulation outcome. About 12% enhancement in pressure drop and up to 51% improvement in thermal resistance is reported for the optimized plate fin heat sink as per data manifested.

scholarly journals Simulation Study on Liquid Cooling of Lithium-ion Battery Pack with a Novel Pipeline Structure

2021 ◽  
Vol 2125 (1) ◽  
pp. 012062
Author(s):  
Chao Lv ◽  
Tianyuan Xia ◽  
Hongxin Yin ◽  
Minghe Sun
Keyword(s):  
Lithium Ion Battery ◽  
Flow Rate ◽  
Temperature Difference ◽  
Heat Dissipation ◽  
Lithium Ion ◽  
Battery Pack ◽  
Maximum Temperature ◽  
Coolant Temperature ◽  
Temperature Uniformity ◽  
Liquid Cooling

Abstract Lithium-ion battery is widely used as the mainstream power source of electric vehicles owing to its high specific energy and low self-discharge rate. However, the performance of the lithium-ion battery is largely hindered by its heat dissipation issue. In this paper, lithium-ion battery pack with main channel and multi-branch channel based on liquid cooling sys-tem is studied. Further, numerical simulation was used to analyze the effects of coolant temperature and flow rate on cooling performance. Based on the original pipeline structure, a new pipeline structure was proposed in the present work. The results show that increasing the cool-ant flow rate not only reduces the maximum temperature of the battery pack, but also reduces the temperature difference. Lowering the coolant temperature could largely decrease the maximum temperature of the battery pack, but it tends to widen the temperature difference and worsen the temperature uniformity. Up-on comparison, maximum temperature is found to be decreased by 0.44K, whereas, the temperature difference of the battery decreased and the temperature uniformity is improved.

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