Heat Transfer Performance of Aluminum Foams

2011 ◽  
Vol 133 (6) ◽  
Author(s):  
Simone Mancin ◽  
Claudio Zilio ◽  
Luisa Rossetto ◽  
Alberto Cavallini
Keyword(s):  
Heat Transfer ◽  
Experimental Data ◽  
Pressure Drop ◽  
Fluid Dynamic ◽  
Foam Core ◽  
Aluminum Foams ◽  
Experimental Heat ◽  
High Heat Transfer ◽  
Experimental Heat Transfer ◽  
Core Height

Because of their interesting heat transfer and mechanical properties, metal foams have been proposed for several different applications, thermal and structural. This paper aims at pointing out the effective thermal fluid dynamic behavior of these new enhanced surfaces, which present high heat transfer area per unit of volume at the expense of high pressure drop. The paper presents the experimental heat transfer and pressure drop measurements relative to air flowing in forced convection through four different aluminum foams, when electrically heated. The tested aluminum foams present 5, 10, 20 and 40 PPI (pores per inch), porosity around 0.92–0.93, and 0.02 m of foam core height. The experimental heat transfer coefficients and pressure drops have been obtained by varying the air mass flow rate and the electrical power, which has been set at 25.0 kW m−2, 32.5 kW m−2, and 40.0 kW m−2. The results have been compared against those measured for 40 mm high samples, in order to study the effects of the foam core height on the heat transfer. Moreover, predictions from two recent models are compared with heat transfer coefficient and pressure drop experimental data. The predictions are in good agreement with experimental data.

Experimental Study of Turbulent Flow Heat Transfer and Pressure Drop in a Plate Heat Exchanger With Chevron Plates

1999 ◽  
Vol 121 (1) ◽  
pp. 110-117 ◽  
Author(s):  
A. Muley ◽  
R. M. Manglik
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Pressure Drop ◽  
Flat Plate ◽  
Plate Heat Exchanger ◽  
Plate Heat ◽  
Experimental Heat ◽  
Experimental Heat Transfer ◽  
Flow Heat ◽  
Phase Water

Experimental heat transfer and isothermal pressure drop data for single-phase water flows in a plate heat exchanger (PHE) with chevron plates are presented. In a single-pass U-type counterflow PHE, three different chevron plate arrangements are considered: two symmetric plate arrangements with β = 30 deg/30 deg and 60 deg/60 deg, and one mixed-plate arrangement with β = 30 deg/60 deg. For water (2 < Pr < 6) flow rates in the 600 < Re < 104 regime, data for Nu and f are presented. The results show significant effects of both the chevron angle β and surface area enlargement factor φ. As β increases, and compared to a flat-plate pack, up to two to five times higher Nu are obtained; the concomitant f, however, are 13 to 44 times higher. Increasing φ also has a similar, though smaller effect. Based on experimental data for Re a 7000 and 30 deg ≤ β ≤ 60 deg, predictive correlations of the form Nu = C1,(β) D1(φ) Rep1(β)Pr1/3(μ/μw)0.14 and f = C2(β) D2(φ) Rep2(β) are devised. Finally, at constant pumping power, and depending upon Re, β, and φ, the heat transfer is found to be enhanced by up to 2.8 times that in an equivalent flat-plate channel.

scholarly journals The analysis of thermal and flow characteristics of the condensation of refrigerant zeotropic mixtures in minichannels

2016 ◽  
Vol 37 (2) ◽  
pp. 41-69 ◽  
Author(s):  
Tadeusz Bohdal ◽  
Katarzyna Widomska ◽  
Małgorzata Sikora
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Pressure Drop ◽  
Transfer Coefficient ◽  
Flow Characteristics ◽  
Internal Diameter ◽  
Test Results ◽  
Experimental Heat ◽  
Experimental Heat Transfer ◽  
Calculation Results

Abstract The paper presents the results of experimental heat transfer and pressure drop during condensation of the single component refrigerant R134a and zeotropic mixtures R404A, R407C, and R410A in tube minichannels of internal diameter from the range 0.31-3.30 mm. The local values and the average of heat transfer coefficient and pressure drop in the whole range of the change in mass quality were measured. On the basis of the obtained test results there was illustrated the influence of the change of mass vapor quality, the mass flux density, and the inner diameter of channel on the studied parameters. These results were compared with the calculation results based on the relations postulated by other authors. The discrepancy range was ± 50%. On the basis of given test results own correlation was developed to calculate the heat transfer coefficient and pressure drop of tested refrigerants which presents the obtained results in a range of discrepancy of ±25%.

Convective Air Heat Transfer Through 10 PPI Aluminum Foams

2010 ◽  
Author(s):  
Simone Mancin ◽  
Claudio Zilio ◽  
Luisa Rossetto ◽  
Alberto Cavallini
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Rectangular Cross Section ◽  
Open Circuit ◽  
Bottom Plate ◽  
Foam Core ◽  
Aluminum Foams ◽  
Transfer Coefficients ◽  
Experimental Heat

This paper presents the experimental heat transfer coefficient and pressure drop measurements obtained during single phase air heat transfer through four 10 pores per inch (PPI) metal foams with different porosities and different foam core heights, 40 mm and 20 mm respectively. The specimens have been inserted in an open-circuit type wind channel with rectangular cross section. The effect of the foam core height on the heat transfer has been analysed by imposing three constant heat flow rates at the bottom plate of the samples: 250, 325 and 400 W and varying the air mass velocity between 0.005 and 0.025 kg m−2 s−1 at around atmospheric pressure. The temperatures of the base, of the upper plate and of the air, at the inlet and outlet of the test section, have been measured by means of several T-type calibrated thermocouples. The pressure drops during air flow through the samples are recorded by means of a high accuracy differential pressure transducer. The experimental results are presented in terms of heat transfer coefficient, normalised mean wall temperature, pressure gradient, permeability and inertia coefficient. The measured pressure gradients and heat transfer coefficients have been compared against the predictions of two different models recently developed by present authors.

On Partially Corrugated Ducts in Heat Exchangers

2002 ◽  
Author(s):  
Bengt Sunden
Keyword(s):  
Heat Transfer ◽  
Pressure Drop ◽  
Heat Exchangers ◽  
Main Idea ◽  
Transfer Enhancement ◽  
Regenerative Heat ◽  
Experimental Heat ◽  
Experimental Heat Transfer ◽  
Increased Pressure ◽  
Hydraulic Balance

In this paper the concept of partially corrugated ducts for heat exchanger applications is discussed. The main idea is that using partially corrugated ducts instead of ducts with continuous corrugation provides a method to achieve a better balance between heat transfer enhancement and increased pressure drop penalty. The origin of the work stems from rotary regenerative heat exchangers. The present paper focuses on this matter and numerical results (based on CFD) as well as preliminary experimental heat transfer data (overall), available mass transfer results are used to support the discussions and conclusions. It is found that partially corrugated ducts might be an alternative to ducts with continuous corrugation in some cases and then present a way to control the thermal hydraulic balance. How to take advantage of the increased pressure drop is discussed briefly.

An Experimental Study of Forced-Convection Heat Transfer From a Sphere to Liquid Sodium

1968 ◽  
Vol 90 (1) ◽  
pp. 9-12 ◽  
Author(s):  
L. C. Witte
Keyword(s):  
Heat Transfer ◽  
Experimental Data ◽  
Convection Heat Transfer ◽  
Reynolds Numbers ◽  
Liquid Sodium ◽  
Convection Heat ◽  
Transfer Rates ◽  
Experimental Heat ◽  
Experimental Heat Transfer ◽  
Heated Metal

Experimental heat-transfer rates from spheres moving through liquid sodium have been obtained. The experimental data were obtained by a transient technique in which a heated metal sphere was passed through a pool of liquid sodium. Heat-transfer rates up to 3.58 × 106 Btu/(hr)(ft2) were calculated from the experimental measurements. Reynolds numbers, based on the sphere velocity and diameter, ranged from 35,000 to 153,000. The experimental data were correlated by an expression similar to theoretical expressions obtained from potential-flow theory.

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