Laminar-Transitional Convection From Repeated Ribs in a Channel

1992 ◽  
Vol 114 (1) ◽  
pp. 29-34 ◽  
Author(s):  
R. A. Wirtz ◽  
Weiming Chen
Keyword(s):  
Heat Transfer ◽  
Pressure Drop ◽  
Three Dimensional ◽  
Electronic Packages ◽  
Average Heat Transfer Coefficient ◽  
Pumping Power ◽  
Low Profile ◽  
Linear Correlations ◽  
Transfer Pressure ◽  
Wall Spacing

Velocimetry, heat transfer, and pressure drop experiments are reported for laminar/transitional air flow in a channel containing rectangular transverse ribs located along one channel wall. The geometry is intended to represent an array of low profile electronic packages. At fixed pumping power per unit channel volume, the heat transfer rate per unit volume is independent of rib-to-rib spacing and increases with decreasing wall-to-wall spacing. The fully developed, rib-average heat transfer coefficient is found to be linearly related to the maximum streamwise rms turbulence measured above the rib-tops. Linear correlations, in terms of a descriptor of the rms streamwise turbulence, are shown to unify heat transfer/pressure drop data for channels containing either two-or three-dimensional protrusions.

Pressure Drop and Heat Transfer Characteristics of Louvered Fin Heat Exchangers

2013 ◽  
Vol 465-466 ◽  
pp. 500-504 ◽  
Author(s):  
Shahrin Hisham Amirnordin ◽  
Hissein Didane Djamal ◽  
Mohd Norani Mansor ◽  
Amir Khalid ◽  
Md Seri Suzairin ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Pressure Drop ◽  
Heat Transfer Rate ◽  
Heat Exchangers ◽  
Transfer Rate ◽  
Three Dimensional ◽  
Considerable Effect ◽  
Heat Transfer Characteristics ◽  
Transfer Characteristics ◽  
Louvered Fin

This paper presents the effect of the changes in fin geometry on pressure drop and heat transfer characteristics of louvered fin heat exchanger numerically. Three dimensional simulation using ANSYS Fluent have been conducted for six different configurations at Reynolds number ranging from 200 to 1000 based on louver pitch. The performance of this system has been evaluated by calculating pressure drop and heat transfer coefficient. The result shows that, the fin pitch and the louver pitch have a very considerable effect on pressure drop as well as heat transfer rate. It is observed that increasing the fin pitch will relatively result in an increase in heat transfer rate but at the same time, the pressure drop will decrease. On the other hand, low pressure drop and low heat transfer rate will be obtained when the louver pitch is increased. Final result shows a good agreement between experimental and numerical results of the louvered fin which is about 12%. This indicates the capability of louvered fin in enhancing the performance of heat exchangers.

CFD Aided Design of Heat Transfer Plates for Gasketed Plate Heat Exchangers

2014 ◽  
Author(s):  
Ece Özkaya ◽  
Selin Aradag ◽  
Sadik Kakac
Keyword(s):  
Heat Transfer ◽  
Pressure Drop ◽  
Heat Exchangers ◽  
Three Dimensional ◽  
Separate Flow ◽  
Working Fluid ◽  
Number Range ◽  
Plate Heat ◽  
Pressure Distributions ◽  
Cfd Analyses

In this study, three-dimensional computational fluid dynamics (CFD) analyses are performed to assess the thermal-hydraulic characteristics of a commercial Gasketed Plate Heat Exchangers (GPHEx) with 30 degrees of chevron angle (Plate1). The results of CFD analyses are compared with a computer program (ETU HEX) previously developed based on experimental results. Heat transfer plate is scanned using photogrammetric scan method to model GPHEx. CFD model is created as two separate flow zones, one for each of hot and cold domains with a virtual plate. Mass flow inlet and pressure outlet boundary conditions are applied. The working fluid is water. Temperature and pressure distributions are obtained for a Reynolds number range of 700–3400 and total temperature difference and pressure drop values are compared with ETU HEX. A new plate (Plate2) with corrugation pattern using smaller amplitude is designed and analyzed. The thermal properties are in good agreement with experimental data for the commercial plate. For the new plate, the decrease of the amplitude leads to a smaller enlargement factor which causes a low heat transfer rate while the pressure drop remains almost constant.

Fluid Flow and Heat Transfer Analysis of Automotive Radiator Using CFD Tools

2005 ◽  
Author(s):  
V. P. Malapure ◽  
A. Bhattacharya ◽  
Sushanta K. Mitra
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Pressure Drop ◽  
Transfer Coefficient ◽  
Temperature Drop ◽  
Three Dimensional ◽  
Heat Transfer Analysis ◽  
Coolant Temperature ◽  
Flow And Heat Transfer ◽  
Optimization Study

This paper presents a three-dimensional numerical analysis of flow and heat transfer over plate fins in a compact heat exchanger used as a radiator in the automotive industry. The aim of this study is to predict the heat transfer and pressure drop in the radiator. FLUENT 6.1 is used for simulation. Several cases are simulated in order to investigate the coolant temperature drop, heat transfer coefficient for the coolant and the air side along with the corresponding pressure drop. It is observed that the heat transfer and pressure drop fairly agree with experimental data. It is also found that the fin temperature depends on the frontal air velocity and the coolant side heat transfer coefficient is in good agreement with classical Dittus–Boelter correlation. It is also found that the specific dissipation increases with the coolant and the air flow rates. This work can further be extended to perform optimization study for radiator design.

Measurements and Numerical Simulations of Heat Transfer and Pressure Drop in a Duct With Smooth Walls

2017 ◽  
Author(s):  
Puxuan Li ◽  
Steve J. Eckels
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Pressure Drop ◽  
Transfer Coefficient ◽  
Numerical Models ◽  
Convective Heat Transfer Coefficient ◽  
Three Dimensional ◽  
Reynolds Numbers ◽  
Inlet Temperature ◽  
Ansys Fluent

Accurate measurements of heat transfer and pressure drop play important roles in thermal designs in a variety of pipes and ducts. In this study, the convective heat transfer coefficient was measured with a semi-local surface average based on Newton’s Law of cooling. Flow and heat transfer data for different Reynolds numbers were collected and compared in a duct with smooth walls. Pressure drop was measured with a pressure transducer from OMEGA Engineering Inc. The experimental results were compared with numerical estimations generated in ANSYS Fluent. Fluent contains the broad physical modeling capabilities needed to model heat transfer and pressure drop in the duct. Thermal conduction and convection in the three-dimensional (3D) duct are simulated together. Special cares for selecting the viscosity models and the near-wall treatments are discussed. The goal of the paper is to find appropriate numerical models for simulating heat conduction, heat convection and pressure drop in the duct with different Reynolds numbers. The relationship between the heat transfer coefficient and Reynolds numbers is discussed. Heat flux and inlet temperature measured in the experiment are applied to the boundary conditions. The study provides the unique opportunity to verify the accuracy of numerical models on heat transfer and pressure drop in ANSYS Fluent.

Experimental Investigation of Crossflow Diverters in Jet Impingement Cooling

2019 ◽  
Author(s):  
Srivatsan Madhavan ◽  
Kishore Ranganath Ramakrishnan ◽  
Prashant Singh ◽  
Srinath V. Ekkad
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Pressure Drop ◽  
Transfer Coefficient ◽  
Turbine Blades ◽  
Jet Impingement ◽  
Target Surface ◽  
Pumping Power ◽  
Detailed Measurement ◽  
To Come

Abstract Jet impingement is a cooling technique commonly employed in combustor liner cooling and high-pressure gas turbine blades. However, jets from upstream impingement holes reduce the effectiveness of downstream jets due to jet deflection in the direction of crossflow. In order to avoid this phenomenon and provide an enhanced cooling on the target surface, we have attempted to come up with a novel design called “crossflow diverters”. Crossflow diverters are U-shaped ribs that are placed between jets in the crossflow direction (under maximum crossflow condition). In this study, the baseline case is jet impingement onto a smooth surface with 10 rows of jet impingement holes, jet-to-jet spacing of X/D = Y/D = 6 and jet-to-target spacing of Z/D = 2. Crossflow diverters with thickness ‘t’ of 1.5875 mm, height ‘h’ of 2D placed in the streamwise direction at a distance of X = 2D from center of the jet have been investigated experimentally. Transient liquid crystal thermography technique has been used to obtain detailed measurement of heat transfer coefficient for four jet diameter based Reynolds numbers of 3500, 5000, 7500, 12000. It has been observed that crossflow diverters protect the downstream jets from upstream jet deflection thereby maximizing their stagnation cooling potential. An average of 15–30% enhancement in Nusselt number is obtained over the flow range tested. However, this comes at the expense of increase in pumping power. Pressure drop for the enhanced geometry is 1–1.5 times the pressure drop for baseline impingement case. At a constant pumping power, crossflow diverters produce 9–15% enhancement in heat transfer coefficient as compared to baseline smooth case.

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