A Comparison of Computational and Experimental Results for Flow and Heat Transfer From an Array of Heated Blocks

1997 ◽  
Vol 119 (1) ◽  
pp. 32-39 ◽  
Author(s):  
A. M. Anderson
Keyword(s):  
Heat Transfer ◽  
Experimental Data ◽  
Control Volume ◽  
Computer Code ◽  
Experimental Results ◽  
Convection Flow ◽  
Channel Height ◽  
Computational Results ◽  
Adiabatic Wall ◽  
Flow And Heat Transfer

This paper summarizes computational results for flow and heat transfer over an array ofidealized electronic components and compares them to experimental data. The numerical modeling was performed using a commercial finite control volume computer code (Flotherm1, by Flomerics) and the results are compared to a set of experimental data. The experimental model consists of a uniform array of eight rows by six columns of solid aluminum blocks (9.5 mm high × 46.5 mm wide × 37.5 mm long) mounted on an adiabatic wall of a channel in forced convection flow. Four channel heights (H/B = 1.5–4.6) and a range of inlet velocities (3.0 to 8.1 m/s) were modelled. The flow was modeled as turbulent flow using the κ-ε turbulence model. Data for the adiabatic heat transfer coefficient had, the superposition kernel function g*, and the channel pressure drop ΔP are compared. The computational results for had are in excellent agreement with the experimental data (within about five percent on average). The computationalresults for g* predict the correct trends (roll off with downstream distance, channel height dependence, and velocity independence). However, values are as much as 50 percent higher than the experimental results which means the computational model under-predicts the amount of cross channel mixing. Computational results for ΔP compare reasonably well (within 20 percent on average).

Numerical and Experimental Studies of Fluid Flow and Heat Transfer in a Model Experiment for Hydrothermal Growth

2016 ◽  
Vol 254 ◽  
pp. 237-242
Author(s):  
Daniel Ursu ◽  
Radu Negrila ◽  
Alexandra Popescu ◽  
Ioan Grozescu ◽  
Daniel Vizman
Keyword(s):  
Heat Transfer ◽  
Fluid Flow ◽  
Natural Convection ◽  
Temperature Difference ◽  
Experimental Studies ◽  
Experimental Results ◽  
Convection Flow ◽  
Bottom Part ◽  
Flow And Heat Transfer ◽  
Liquid Flows

Understanding of the natural convection flow in hydrothermal autoclaves is essential for the control of the growth rate and the quality of the grown crystals. This paper presents an analysis of the natural convection fluid flow and heat transfer and show the comparison between simulation and experimental results for the experimental model in a small size autoclaves, fill with water. A numerical model based on finite volume method has been developed to simulate the heat transfer and fluid convection in the vessel. Results show that the flow will strongly affect the temperature distribution. It can be observed that in the upper region the liquid flows up in the middle of the vessel and flows down in lateral parts near the walls. The temperature difference between experimental and simulation results is less than 1 °C in the upper part and between 2 and 3 °C in the bottom part. Velocity measurements show a good qualitative agreement between simulation and experimental results. The value of the z-component of velocity along the symmetry axis slightly increase with the increases of temperature difference ΔT .

On Correlating Experimental Pressure Flow and Heat Transfer Measurements From Silicon Microchannels With Theoretical Calculations

2007 ◽  
Author(s):  
Cormac Eason ◽  
Niall O’Keeffe ◽  
Ryan Enright ◽  
Tara Dalton
Keyword(s):  
Heat Transfer ◽  
Confidence Interval ◽  
Theoretical Calculations ◽  
Experimental Results ◽  
Channel Height ◽  
Outlet Temperature ◽  
Fluid Temperature ◽  
Pressure Flow ◽  
Flow And Heat Transfer ◽  
Fluid Properties

The bulk pressure flow and heat transfer characteristics of rectangular and trapezoidal microchannels etched in silicon were measured in the laminar regime. The channel hydraulic diameters were 305 μm for the Deep Reactive Ion Etched (DRIE) etched channel and 317 μm for the wet etched channel and there were 22 channels in each sample. The fluid used was purified degassed water. The inlet and outlet temperature and pressure of the fluid and the wall temperatures of the channels were measured at the inlet and outlet of the channels. Theoretical and experimental results were calculated using fluid properties at the mean fluid temperature for each data point. These were then collapsed to a single curve at constant temperature by multiplying the measured value by the ratio of the relevant fluid properties at the experimental and required temperatures. The cross section of each channel on each channel sample was measured along with the channel height and width to give an area ratio between the actual channel width and the width calculated assuming the channel was perfectly rectangular or trapezoidal. This ratio is used to compensate the theoretical results and improve their correlation with the experiment. The uncertainty in the experimental results was calculated by running the result processing calculations three times, once at nominal values and then shifting input values to their upper and lower limits based on a 95% confidence interval on the standard deviation for each inputted measurement. Theoretical calculations were run for each experimental mass flow rate in order to produce equivalent theoretical points to the experimental values. Uncertainty in the theory is also determined by running the theoretical calculations at upper, lower and nominal 95% confidence interval values for the channels being tested. It was found that while the pressure flow data from the channels matched theoretical trends and that the results for the rectangular DRIE channels showed no experimentally significant deviation from theory, the experimental data from the wet etched trapezoidal channels was lower than predictions. The heat transfer from the channels is strongly affected by the heat transferred to the coolant by the manifolds. When this effect is removed, the experimental Reynolds number Nusselt number plot becomes strongly linear. This does not agree with theoretical predictions.

scholarly journals Investigations of Flow and Heat Transfer Characteristics in a Channel Impingement Cooling Configuration with a Single Row of Water Jets

Energies ◽  
2021 ◽  
Vol 14 (14) ◽  
pp. 4327
Author(s):  
Min-Seob Shin ◽  
Santhosh Senguttuvan ◽  
Sung-Min Kim
Keyword(s):  
Heat Transfer ◽  
Local Heat Transfer ◽  
Target Surface ◽  
Channel Height ◽  
Heat Transfer Characteristics ◽  
Transfer Coefficients ◽  
Impingement Cooling ◽  
Average Heat ◽  
Transfer Characteristics ◽  
Flow And Heat Transfer

The present study experimentally and numerically investigates the effect of channel height on the flow and heat transfer characteristics of a channel impingement cooling configuration for various jet Reynolds numbers in the range of 2000–8600. A single array consisting of eleven jets with 0.8 mm diameter injects water into the channel with 2 mm width at four different channel heights (3, 4, 5, and 6 mm). The average heat transfer coefficients at the target surface are measured by maintaining a temperature difference between the jet exit and the target surface in the range of 15–17 °C for each channel height. The experimental results show the average heat transfer coefficient at the target surface increases with the jet Reynolds number and decreases with the channel height. An average Nusselt number correlation is developed based on 85 experimentally measured data points with a mean absolute error of less than 4.31%. The numerical simulation accurately predicts the overall heat transfer rate within 10% error. The numerical results are analyzed to investigate the flow structure and its effect on the local heat transfer characteristics. The present study advances the primary understanding of the flow and heat transfer characteristics of the channel impingement cooling configuration with liquid jets.

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