A Simple Thermal Resistance Model for Open Cell Metal Foams

2013 ◽  
Vol 135 (3) ◽  
Author(s):  
Pradeep. M. Kamath ◽  
C. Balaji ◽  
S. P. Venkateshan
Keyword(s):  
Heat Transfer ◽  
Thermal Resistance ◽  
Contact Resistance ◽  
Convective Heat Transfer Coefficient ◽  
Vertical Channel ◽  
Metal Foams ◽  
Experimental Results ◽  
Actual Case ◽  
Open Cell ◽  
Resistance Model

This paper presents a methodology for obtaining the convective heat transfer coefficient from the wall of a heated aluminium plate, placed in a vertical channel filled with open cell metal foams. For accomplishing this, a thermal resistance model from literature for metal foams is suitably modified to account for contact resistance. The contact resistance is then evaluated using the experimental results. A correlation for the estimation of the contact resistance as a function of the pertinent parameters, based on the above approach is developed. The model is first validated with experimental results in literature for the asymptotic case of negligible contact resistance. A parametric study of the effect of different foam parameters on the heat transfer is reported with and without the presence of contact resistance. The significance of the effect of contact resistance in the mixed convection and forced convection regimes is discussed. The procedure to employ the present methodology in an actual case is demonstrated and verified with additional, independent experimental data.

Piston-Liner Thermal Resistance Model for Diesel Engine Simulation: Part 1: Formulation and Tuning

1991 ◽  
Vol 205 (5) ◽  
pp. 343-352 ◽  
Author(s):  
Y Rasihhan ◽  
F J Wallace
Keyword(s):  
Heat Transfer ◽  
Diesel Engine ◽  
Thermal Resistance ◽  
Direct Injection ◽  
Transfer Model ◽  
Conductive Heat ◽  
Axially Symmetric ◽  
Engine Simulation ◽  
Axial Movement ◽  
Resistance Model

A simple, effective and computationally economical piston-liner thermal resistance model for diesel engine simulation is described. In the model, the detailed shape of the piston and its axial movement and interaction with liner nodes are all taken into account. An imaginary node within the piston provides the necessary temperature difference between the piston and the liner nodes for conductive heat transfer, which is expected to reverse its direction with liner insulation. In the liner, an axially symmetric two-dimensional heat-transfer model is used. Later the piston-liner model is tuned for the experimental single cylinder, direct injection, Petter PH 1W engine used at Bath University, against the experimental piston temperature and liner temperature distribution.

scholarly journals A Fast Prediction Model for Heat Transfer of Hot-Wall Heat Exchanger Based on Analytical Solution

2018 ◽  
Vol 9 (1) ◽  
pp. 72 ◽  
Author(s):  
Wenju Hu ◽  
Peng Jia ◽  
Jinzhe Nie ◽  
Yan Gao ◽  
Qunli Zhang
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Thermal Resistance ◽  
Heat Conductivity ◽  
Convective Heat Transfer Coefficient ◽  
Side Wall ◽  
Analytic Solutions ◽  
Heat Convection ◽  
Thermal Engineering ◽  
Fast Prediction

The hot-wall heat exchanger (HWHE) has been widely used in thermal engineering fields such as ceiling radiant heating/cooling, refrigerator condenser, solar heat collection, and high-temperature heat recovery. However, the numerical simulation normally used for heat transfer prediction in HWHE is usually not as convenient as the analytic solutions in engineering applications. In this paper, a new heat transfer mathematical model of HWHE-based on analytic solutions was developed, which could be much faster to obtain the heat transfer properties of HWHE. The proposed model was validated under four conditions with literature values, which showed that the deviations of heat flux are 2.53%, 0.99%, 2.12%, and 1.96%, indicating its accuracy is satisfied. The model was then used to analyze the thermal property of HWHE. The results show the thermal resistance caused by panel with heat convection and conduction accounts for 96.54% of HWHE thermal resistance, and the thermal resistance caused by heat convection on the surface of panel is 74.43%. The analyzation results also show that adding aluminum foil around pipes could decrease HWHE thermal resistance by 5.11%. Besides, the influence of pipe diameters, pipe distance, pipe heat conductivity, side wall heat conductivity, and convective heat transfer coefficient on the heat transfer performance of HWHE was analyzed. The research in this paper can be used for fast prediction and optimization of heat transfer in HWHE.

Convective Heat Transfer Characteristics of Silver-Water Nanofluid Under Laminar and Turbulent Flow Conditions

2012 ◽  
Vol 4 (3) ◽  
Author(s):  
Lazarus Godson ◽  
B. Raja ◽  
D. Mohan Lal ◽  
S. Wongwises
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Pressure Drop ◽  
Turbulent Flow ◽  
Transfer Coefficient ◽  
Convective Heat Transfer ◽  
Convective Heat ◽  
Pure Water ◽  
Convective Heat Transfer Coefficient ◽  
Experimental Results

The convective heat transfer coefficient and pressure drop of silver-water nanofluids is measured in a counter flow heat exchanger from laminar to turbulent flow regime. The experimental results show that the convective heat transfer coefficient of the nanofluids increases by up to 69% at a concentration of 0.9 vol. % compared with that of pure water. Furthermore, the experimental results show that the convective heat transfer coefficient enhancement exceeds the thermal conductivity enhancement. It is observed that the measured heat transfer coefficient is higher than that of the predicted ones using Gnielinski equation by at least 40%. The use of the silver nanofluid has a little penalty in pressure drop up to 55% increase 0.9% volume concentration of silver nanoparticles.

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