Characterization of Porous Carbon Foam as a Material for Compact Recuperators

2006 ◽  
Vol 129 (2) ◽  
pp. 326-330 ◽  
Author(s):  
A. G. Straatman ◽  
N. C. Gallego ◽  
Q. Yu ◽  
B. E. Thompson
Keyword(s):  
Heat Transfer ◽  
Pressure Drop ◽  
Porous Carbon ◽  
Aluminum Foam ◽  
Carbon Foam ◽  
Small Scale ◽  
Base Temperature ◽  
Extended Surface ◽  
Surface Convection

Experiments are presented to quantify the convective heat transfer and hydrodynamic loss that is obtained by forcing water through blocks of porous carbon foam (PCF) heated from one side. The experiments were conducted in a small-scale water tunnel instrumented to measure the pressure drop and temperature rise of the water passing through the blocks and the base temperature and heat flux into the foam block. In comparison to similar porosity aluminum foam, the present results indicate that the pressure drop across the porous carbon foam is higher due to the large hydrodynamic loss associated with the cell windows connecting the pores, but the heat transfer performance suggests that there may be a significant advantage to using PCF over aluminum foam for extended surface convection elements in recuperators and electronic cooling devices.

Characterization of Porous Carbon Foam as a Material for Compact Recuperators

2006 ◽  
Author(s):  
A. G. Straatman ◽  
N. C. Gallego ◽  
Q. Yu ◽  
B. E. Thompson
Keyword(s):  
Heat Transfer ◽  
Pressure Drop ◽  
Porous Carbon ◽  
Aluminum Foam ◽  
Carbon Foam ◽  
Small Scale ◽  
Base Temperature ◽  
Extended Surface ◽  
Surface Convection

Experiments are presented to quantify the convective heat transfer and the hydrodynamic loss that is obtained by forcing water through blocks of porous carbon foam (PCF) heated from one side. The experiments were conducted in a small-scale water tunnel instrumented to measure the pressure drop and the temperature rise of the water passing through the blocks and the base temperature and heat flux into the foam block. In comparison to similar porosity aluminum foam, the present results indicate that the pressure drop across the porous carbon foam is higher due to the large hydrodynamic loss associated with the cell windows connecting the pores, but the heat transfer performance suggests that there may be a significant advantage to using PCF over aluminum foam for extended surface convection elements in recuperators and electronic cooling devices.

Forced Convection Heat Transfer and Hydraulic Losses in Graphitic Foam

2006 ◽  
Vol 129 (9) ◽  
pp. 1237-1245 ◽  
Author(s):  
A. G. Straatman ◽  
N. C. Gallego ◽  
Q. Yu ◽  
L. Betchen ◽  
B. E. Thompson
Keyword(s):  
Heat Transfer ◽  
Pressure Drop ◽  
Aluminum Foam ◽  
Solid Phase ◽  
Thin Layers ◽  
Small Scale ◽  
Hydraulic Loss ◽  
Base Temperature ◽  
Extended Surface ◽  
Graphitic Foam

Experiments and computations are presented to quantify the convective heat transfer and the hydraulic loss that is obtained by forcing water through blocks of graphitic foam (GF) heated from one side. Experiments have been conducted in a small-scale water tunnel instrumented to measure the pressure drop and the temperature rise of water passing through the foam and the base temperature and heat flux into the foam block. The experimental data were then used to calibrate a thermal non-equilibrium finite-volume model to facilitate comparisons between GF and aluminum foam. Comparisons of the pressure drop indicate that both normal and compressed aluminum foams are significantly more permeable than GF. Results of the heat transfer indicate that the maximum possible heat dissipation from a given surface is reached using very thin layers of aluminum foam due to the inability of the foam to entrain heat into its internal structure. In contrast, graphitic foam is able to entrain heat deep into the foam structure due to its high extended surface efficiency and thus much more heat can be transferred from a given surface area. The higher extended surface efficiency is mainly due to the combination of moderate porosity and higher solid-phase conductivity.

Thermal characterization of porous carbon foam—convection in parallel flow

2006 ◽  
Vol 49 (11-12) ◽  
pp. 1991-1998 ◽  
Author(s):  
A.G. Straatman ◽  
N.C. Gallego ◽  
B.E. Thompson ◽  
H. Hangan
Keyword(s):  
Porous Carbon ◽  
Carbon Foam ◽  
Thermal Characterization ◽  
Parallel Flow

scholarly journals CFD Characterization of Pressure Drop and Heat Transfer Inside Porous Substrates

2015 ◽  
Vol 81 ◽  
pp. 836-845 ◽  
Author(s):  
A. Della Torre ◽  
G. Montenegro ◽  
A. Onorati ◽  
G. Tabor
Keyword(s):  
Heat Transfer ◽  
Pressure Drop ◽  
Porous Substrates

scholarly journals Validation of a CFD Model Predicting the Effect of High Level Lateral Acceleration Sloshing on the Heat Transfer and Pressure Drop in a Small-Scale Tank in Normal Gravity

2018 ◽  
Author(s):  
O. Kartuzova ◽  
M. Kassemi
Keyword(s):  
Heat Transfer ◽  
Pressure Drop ◽  
Current Model ◽  
Lateral Acceleration ◽  
Small Scale ◽  
Cfd Model ◽  
Two Phase ◽  
Large Eddy Simulation Model ◽  
Tank Pressure ◽  
High Level

A two-phase CFD model is developed to study the effects of sloshing with high level lateral acceleration on the heat transfer and pressure drop in a small scale tank. Computational results are compared to the data provided by a non-isothermal sloshing experiment without phase change conducted by T. Himeno et al. at the University of Tokyo and JAXA in 2011 [1]. The results of the current model are, also, compared to CFD predictions reported by Himeno et al. [2]. A step change in lateral acceleration was applied in the experiment. Different levels of lateral acceleration amplitude, varying between 0G and 0.5G, were considered. CFD results for interface movement and tank pressure are presented and compared in this paper to the experimental data for the case in which the value of lateral acceleration was set to 0.5G. The effects of initial and boundary conditions and turbulence modeling approach on the tank pressure change during sloshing are discussed in detail. The effect of conjugate heat transfer in the tank wall is also studied to show its important role in determining the tank pressure evolution. The results of the Reynolds Averaged Navier Stokes (RANS) models are compared to the results of the Large Eddy Simulation model (LES) to underscore the importance of correctly capturing the effects of turbulence for high fidelity predictions.

scholarly journals Automation and heat transfer characterization of immersion mode spectroscopy for analysis of ice nucleating particles

2017 ◽  
Vol 10 (7) ◽  
pp. 2613-2626 ◽  
Author(s):  
Charlotte M. Beall ◽  
M. Dale Stokes ◽  
Thomas C. Hill ◽  
Paul J. DeMott ◽  
Jesse T. DeWald ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Temperature Measurement ◽  
Measurement Technique ◽  
Freezing Temperature ◽  
Water Volume ◽  
Base Temperature ◽  
Heat Transfer Simulation ◽  
Freezing Temperatures ◽  
Transfer Properties

Abstract. Ice nucleating particles (INPs) influence cloud properties and can affect the overall precipitation efficiency. Developing a parameterization of INPs in global climate models has proven challenging. More INP measurements – including studies of their spatial distribution, sources and sinks, and fundamental freezing mechanisms – must be conducted in order to further improve INP parameterizations. In this paper, an immersion mode INP measurement technique is modified and automated using a software-controlled, real-time image stream designed to leverage optical changes of water droplets to detect freezing events. For the first time, heat transfer properties of the INP measurement technique are characterized using a finite-element-analysis-based heat transfer simulation to improve accuracy of INP freezing temperature measurement. The heat transfer simulation is proposed as a tool that could be used to explain the sources of bias in temperature measurements in INP measurement techniques and ultimately explain the observed discrepancies in measured INP freezing temperatures between different instruments. The simulation results show that a difference of +8.4 °C between the well base temperature and the headspace gas results in an up to 0.6 °C stratification of the aliquot, whereas a difference of +4.2 °C or less results in a thermally homogenous water volume within the error of the thermal probe, ±0.2 °C. The results also show that there is a strong temperature gradient in the immediate vicinity of the aliquot, such that without careful placement of temperature probes, or characterization of heat transfer properties of the water and cooling environment, INP measurements can be biased toward colder temperatures. Based on a modified immersion mode technique, the Automated Ice Spectrometer (AIS), measurements of the standard test dust illite NX are reported and compared against six other immersion mode droplet assay techniques featured in Hiranuma et al. (2015) that used wet suspensions. AIS measurements of illite NX INP freezing temperatures compare reasonably with others, falling within the 5 °C spread in reported spectra. The AIS as well as its characterization of heat transfer properties allows higher confidence in accuracy of freezing temperature measurement, allows higher throughput of sample analysis, and enables disentanglement of the effects of heat transfer rates on sample volumes from time dependence of ice nucleation.

Teaching of Extended Surface Heat Transfer Through Laboratory Experiments

2012 ◽  
Author(s):  
Valerie Eveloy ◽  
Peter Rodgers ◽  
Shrinivas Bojanampati
Keyword(s):  
Heat Transfer ◽  
Student Performance ◽  
Teaching Strategy ◽  
Test Facility ◽  
Management Skills ◽  
Performance Improvements ◽  
Numerical Predictions ◽  
Hands On ◽  
Extended Surface

This paper describes a hands-on laboratory thermofluid project which is taught as part of a one-semester, junior-level mechanical engineering course titled Core Measurements Laboratory. The experiment focuses on the characterization of multi-mode heat transfer from a range of cartridge-heated fin geometries cooled by conduction, natural convection and radiation. The project involves the design and construction of the test facility, experimental characterization of fin heat transfer, and comparison of experimental results with corresponding analytical and numerical predictions, with a formal report submitted on completion. The project is undertaken by a team of four students over a five-week period. Emphasis is placed on highlighting potential discrepancies between measurement and predictions, which are inherent in the test configurations considered, reflecting realistic engineering situations. Sample measurement and analysis results are reported in this paper. The teaching strategy employed to integrate fundamental theories with hands-on experiences is described. The effectiveness of the laboratory project in enhancing student learning of heat transfer, engineering analysis of discrepancies between predictions and measurements, and project management skills was demonstrated by monitoring student performance improvements over the duration of the project.

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