Performance Analysis of Single-Phase Space Thermal Radiators and Optimization through Taguchi-Neuro-Genetic Approach

2021 ◽  
pp. 1-18
Author(s):  
P B Chiranjeevi ◽  
Ashok V ◽  
K. Srinivasan ◽  
Thirumalachari Sundararajan
Keyword(s):  
Heat Transfer ◽  
Performance Analysis ◽  
Conjugate Heat Transfer ◽  
Computational Time ◽  
Maximum Diameter ◽  
Genetic Approach ◽  
Pumping Power ◽  
Power Requirement ◽  
Space Applications ◽  
Heat Rejection

Abstract In the thermal management of spacecraft, space thermal radiators play a vital role as heat sinks. A serial radiator with proven advantages in ground applications is proposed and analyzed for space applications. From the performance analysis, specific heat rejection of serial radiator is found to be higher than parallel radiator by 80% for maximum diameter of tube, 47% for maximum thickness of fin, and 75% for maximum pitch of tubes under consideration. Also, serial radiator requires four times higher pumping power than parallel radiator with geometric parameters and a maximum mass flow rate under consideration. In serial radiators, the cross conduction between the fins has a significant effect on its thermal performance. Thus, conjugate heat transfer simulations and optimization operations are to be performed iteratively to optimize the serial radiator, which is computationally costly. To reduce the computational time, Artificial Neural Network is trained using conjugate heat transfer simulations data and combined with the genetic algorithm to perform optimization. Taguchi's orthogonal arrays provided the partial fraction of conjugate heat transfer simulations set to train the ANN. Taguchi-Neuro-Genetic approach, a process that combines the features of three powerful techniques in different optimization phases, is used to optimize both parallel and serial radiators. The optimization aims to obtain a configuration that provides the lowest mass and lowest pumping power requirement for given heat rejection. Optimization results show that the conventional parallel radiator is about 20% heavier and requires about 35% more pumping power than the proposed serial radiator.

Convective Heat Transfer and Pumping Power Requirement Using Nanofluid for the Flow Through Corrugated Channel

2015 ◽  
Author(s):  
Shafi Noor ◽  
M. Monjurul Ehsan ◽  
M. S. Mayeed ◽  
A. K. M. Sadrul Islam
Keyword(s):  
Heat Transfer ◽  
Convective Heat Transfer ◽  
Heat Transfer Rate ◽  
Convective Heat ◽  
Transfer Rate ◽  
Volume Fraction ◽  
Pumping Power ◽  
Power Requirement ◽  
Corrugated Channel ◽  
Flow Through

Convective heat transfer rate for turbulent flow using nanofluid through both plain and corrugated channel has been investigated numerically in the present study. Three different types of nanofluids namely Al2O3-water, TiO2-water and CuO-water of different volume fractions (1%, 2%, 3%, 4% and 5%), are used as the working fluid flowing through the channel. The corrugated channels have wall geometries of trapezoidal shape of different amplitude-wavelength ratios. Grid independence study was carried out for all the geometries. The obtained results in case of base fluid-water flowing through parallel plate channel have been validated with well-established correlations. The study has been conducted by finite volume method to solve the transport equation for the momentum, energy and turbulence quantities using single phase model of the nanofluids where the thermophysical properties of the nanofluids are calculated by using different correlations from the literature. In this study, the heat transfer enhancement using nanofluids compared to that using base fluid-water is presented for a range of Reynolds number- 15000 to 40000. The pumping power required for the flow through the channels increases with the increase in the viscosity of the fluid which justifies the increase in pumping power requirement in case of nanofluids compared to that with water. While using corrugation at the wall of the channels, in addition to the enhancement in the convective heat transfer rate, there is an increase in the pumping power requirement for the same Reynolds number. However, for a given requirement of heat transfer rate, the required pumping power can be reduced by using nanofluids. This study includes the trend and limit of volume fraction of nanofluid during this pumping power reduction phenomenon. The results show that with the increase in the volume fraction of the nanofluids, the convective heat transfer rate increases which is same for all the geometries of the fluid domain. Addition of nanofluid reduces the pumping power requirement for a constant heat transfer rate. The volume fraction of the nanofluids with which the maximum reduction of pumping power takes place at the optimum working condition is also found in the present study. This study draws a comparison among three different nanofluids in terms of the enhancement in the convective heat transfer rate and corresponding pumping power requirement for the flow through the trapezoidal shaped corrugated channel of various amplitude-wavelength ratios in order to find out the best nanofluids for its optimum results within a specified range of working conditions.

scholarly journals Performance comparison of various coolants for louvered fin tube automotive radiator

2017 ◽  
Vol 21 (6 Part B) ◽  
pp. 2871-2881 ◽  
Author(s):  
Rashmi Sahoo ◽  
Pradyumna Ghosh ◽  
Jahar Sarkar
Keyword(s):  
Heat Transfer ◽  
Ethylene Glycol ◽  
Fuel Consumption ◽  
Propylene Glycol ◽  
Sugarcane Juice ◽  
Engine Fuel ◽  
Pumping Power ◽  
Power Requirement ◽  
Engine Efficiency ◽  
Louvered Fin

In the present study, screening of various coolants (water, ethylene glycol, propylene glycol, brines, nanofluid, and sugarcane juice) for louvered fin automotive radiator has been done based on different energetic and exergetic performance parameters. Effects on radiator size, weight and cost as well as engine efficiency and fuel consumption are discussed as well. Results show that the sugarcane juice seems to be slightly better in terms of both heat transfer and pumping power than water and nanofluid, whereas significantly better than ethylene glycol and propylene glycol. For same heat transfer capacity, the pumping power requirement is minimum and vice-versa with sugarcane juice, followed by nanofluid, water, EG and PG. Study on brines shows an opportunity to use water+25% PG based nanofluids for improvement of performance as well as operating range. Replacement of water or brines by using sugarcane juice and water or wa-ter+25% PG based nanofluids will reduce the radiator size, weight and pumping power, which may lead to increase in compactness and overall engine efficiency or reduction in radiator cost and engine fuel consumption. In overall, both sugarcane juice and nanofluid seem to be potential substitutes of water. However, both have some challenges such as long term stability for practical use.

CFD Modeling of the Hydrogen Fast Filling Process for Type 3 Cylinders and Cylinders Lined With Phase Change Material

2019 ◽  
Author(s):  
Miroslaw Liszka ◽  
Aleksandr Fridlyand ◽  
Ambalavanan Jayaraman ◽  
Michael Bonnema ◽  
Chakravarthy Sishtla
Keyword(s):  
Heat Transfer ◽  
Experimental Data ◽  
Phase Change ◽  
Conjugate Heat Transfer ◽  
Cfd Modeling ◽  
Computational Time ◽  
Filling Process ◽  
Transfer Case ◽  
Type 3 ◽  
Experimental Pressure

Abstract A simulation of the fast filling of a 195-liter type 3 tank with hydrogen was completed with ANSYS Fluent as a baseline case for developing a CFD model capable of accurately modeling the hydrogen cylinder filling process. 141-second profiles of mass flow and temperature of the incoming hydrogen flow into the cylinder were prescribed from experimental data previously collected at the Gas Technology Institute (GTI) in Des Plaines, IL. All the simulations were completed with the coupled pressure based algorithm with the K-Omega SST turbulence model and real gas NIST properties (REFPROP) to capture the effects of compressibility of hydrogen during the filling process. Gravity was enabled in the axial direction of the cylinder. The initial pressure and temperature in the cylinder were 124 bar and 292.3 K, respectively, with a target, experimental pressure of 383 bar at the end of the filling. For the initial case, the walls of the cylinder were modelled as adiabatic to reduce the computational effort. The final pressure and temperature of the adiabatic wall case matched the experimental pressure and temperature within approximately 30 bar and 6 degrees, respectively. The overall pressure and temperature profiles over the course of the filling process also provided a good match between the simulation results and experimental data. A conjugate heat transfer case with the aluminum liner as part of the domain and an adiabatic outer wall was attempted in order to capture the heat transfer to the liner. The conjugate heat transfer case provided promising results but was taxing in the computational time needed to simulate the entire filling process. A User Defined Function (UDF) for a simple lumped heat capacitance model was applied at the wall to model the wall temperature and capture the heat transfer occurring to the wall while reducing the time needed to complete the simulation. The final pressure prediction for this case was excellent, within 3 bar of the experimental value, and matched it accurately for the duration of the fill process. The final temperature prediction worsened and exceeded the experimental value by 16 degrees Celsius. The UDF model also allowed the ability to easily explore more exotic liners such as Phase Change Materials (PCM) which were also simulated in this work.

Multi-objective Design Optimization of Branching, Multifloor, Counterflow Microheat Exchangers

2014 ◽  
Vol 136 (10) ◽  
Author(s):  
Abas Abdoli ◽  
George S. Dulikravich
Keyword(s):  
Conjugate Heat Transfer ◽  
Flow Direction ◽  
Heat Removal ◽  
Heat Transfer Analysis ◽  
Multi Objective Optimization ◽  
Pumping Power ◽  
Power Requirement ◽  
Multi Objective ◽  
Removal Capacity ◽  
Temperature Nonuniformity

Heat removal capacity, coolant pumping power requirement, and surface temperature nonuniformity are three major challenges facing single-phase flow microchannel compact heat exchangers. In this paper multi-objective optimization has been performed to increase heat removal capacity, and decrease pumping power and temperature nonuniformity in complex networks of microchannels. Three-dimensional (3D) four-floor configurations of counterflow branching networks of microchannels were optimized to increase heat removal capacity from surrounding silicon substrate (15 × 15 × 2 mm). Each floor has four different branching subnetworks with opposite flow direction with respect to the next one. Each branching subnetwork has four inlets and one outlet. Branching patterns of each of these subnetworks could be different from the others. Quasi-3D conjugate heat transfer analysis has been performed by developing a software package which uses quasi-1D thermofluid analysis and a 3D steady heat conduction analysis. These two solvers were coupled through their common boundaries representing surfaces of the cooling microchannels. Using quasi-3D conjugate analysis was found to require one order of magnitude less computing time than a fully 3D conjugate heat transfer analysis while offering comparable accuracy for these types of application. The analysis package is capable of generating 3D branching networks with random topologies. Multi-objective optimization using modeFRONTIER software was performed using response surface approximation and genetic algorithm. Diameters and branching pattern of each subnetwork and coolant flow direction on each floor were design variables of multi-objective optimization. Maximizing heat removal capacity, while minimizing coolant pumping power requirement and temperature nonuniformity on the hot surface, were three simultaneous objectives of the optimization. Pareto-optimal solutions demonstrate that thermal loads of up to 500 W/cm2 can be managed with four-floor microchannel cooling networks. A fully 3D thermofluid analysis was performed for one of the optimal designs to confirm the accuracy of results obtained by the quasi-3D simulation package used in this paper.

Optimization of 3D Branching Networks of Microchannels for Microelectronic Device Cooling

2010 ◽  
Author(s):  
George S. Dulikravich ◽  
Thomas J. Martin
Keyword(s):  
Heat Transfer ◽  
Conjugate Heat Transfer ◽  
Stokes Equations ◽  
Heated Surface ◽  
Heat Diffusion ◽  
Heat Transfer Analysis ◽  
Pumping Power ◽  
Multi Objective ◽  
Branching Networks ◽  
3D Network

The aim of this work is to present a methodology to develop cost-effective thermal management solutions for microelectronic devices, capable of removing maximum amount of heat and delivering maximally uniform surface temperature distributions. The topological and geometrical characteristics of multiple-story three-dimensional branching networks of microchannels were developed using multi-objective optimization. The design variables which will be subject to optimization in this analysis are the geometric parameters of the microchannel network, i.e. the number of network floors in a 3D network, the amount of branching levels per floor, the connectivity of the cooling channels, their cross-sectional areas and lengths. A conjugate heat transfer analysis software package (CHETSOLP) and an automatic 3D microchannel network generator (3DBNGEN) were developed and coupled with a multi-objective particle-swarm optimization (MOPSO) algorithm with a goal of creating a design tool for 3D networks of optimized coolant flow channels. Numerical algorithms in the conjugate heat transfer solution package include a quasi-1D thermo-fluid solver (COOLNET) and a 3D steady heat diffusion solver, which were validated against results from high-fidelity Navier-Stokes equations solver and analytical solutions for basic fluid dynamics test cases. The conjugate heat transfer solution is achieved by simultaneous prediction of the quasi-1D internal flow-field in the microchannel network and 3D internal temperature field in the solid substrate [1]. Minimization of the pumping power requirement and maximization of total heat removal subject to temperature uniformity (at the heated surface) were the objectives. Pareto-optimal solutions demonstrate that thermal loads of up to 400 W/cm2 can be managed with 3D multi-floor microchannel networks, with pumping power requirements that are up to 50% lower with respect to pumping power requirements in currently used high-performance cooling technologies, such as jet impingement and hybrid impingement-microchannel flow.

Design Optimisation of Finned Channel

2009 ◽  
Author(s):  
K. M. C. Seakher ◽  
L. S. S. Prakash Kumar ◽  
K. S. R. Kali Prasad ◽  
K. H. Manasa ◽  
A. Siva Kumar
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Pressure Drop ◽  
Transfer Coefficient ◽  
Heat Dissipation ◽  
Pumping Power ◽  
Transfer Enhancement ◽  
Power Requirement ◽  
Smooth Channel ◽  
Fin Length

A finned channel has a higher heat transfer coefficient compared to a smooth channel and the increase in this fin height enhances the heat transfer. But this heat transfer enhancement is accompanied by an increase in pressure drop for a series of fins. This requires an increase in pumping power requirement, indicating that there exists an optimum design or length of the fin at which the heat dissipation is maximum. The objective of this paper is to observe the variation of heat transfer with varying sizes of fins. The effect of fin dimensions on heat transfer can be clearly seen in its performance, which is discussed in the paper. The results are obtained by analytical analysis, and some illustrations are dealt with in the paper, which clearly determine the importance of this factor of optimal fin length.

An Air-Based Cavity-Receiver for Solar Trough Concentrators

2010 ◽  
Author(s):  
Roman Bader ◽  
Maurizio Barbato ◽  
Andrea Pedretti ◽  
Aldo Steinfeld
Keyword(s):  
Heat Transfer ◽  
Solar Power ◽  
Power Input ◽  
Absorption Efficiency ◽  
Conservation Equation ◽  
Heat Transfer Fluid ◽  
Inlet Temperature ◽  
Transfer Model ◽  
Pumping Power ◽  
Power Requirement

A cylindrical cavity-receiver containing a tubular absorber that uses air as the heat transfer fluid is proposed for a novel solar trough concentrator design. A numerical heat transfer model is developed to determine the receiver’s absorption efficiency and pumping power requirement. The 2D steady-state energy conservation equation coupling radiation, convection and conduction heat transfer is formulated and solved numerically by finite-difference techniques. The Monte Carlo ray-tracing and radiosity methods are applied to establish the solar radiation distribution and radiative exchange within the receiver. Simulations were conducted for a 50 m-long and 9.5 m-wide collector section with 120°C air inlet temperature, and air mass flows in the range 0.1–1.2 kg/s. Outlet air temperatures ranged from 260 to 601 °C, and corresponding absorption efficiencies varied between 60 and 18%. Main heat losses integrated over the receiver length were due to reflection and spillage at the receiver’s windowed aperture, amounting to 13% and 9% of the solar power input, respectively. The pressure drop along the 50 m module was in the range 0.23 to 11.84 mbar, resulting in isentropic pumping power requirements of 6.45·10−4%–0.395% of the solar power input.

Simulation and Thermal Optimization of a Manifold Microchannel Flat Plate Heat Exchanger

2012 ◽  
Author(s):  
M. A. Arie ◽  
A. H. Shooshtari ◽  
S. V. Dessiatoun ◽  
M. M. Ohadi ◽  
E. Al Hajri
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Flat Plate ◽  
Fluid Dynamic ◽  
Plate Heat Exchanger ◽  
Computational Time ◽  
Single Element ◽  
Pumping Power ◽  
Plate Heat ◽  
Manifold Microchannel

This paper describes a multi-objective optimization of single-phase, laminar flow inside a single element of a manifold microchannel flat plate heat exchanger. Approximation assisted optimization was used for the optimization process. The process uses metamodeling in conjunction with Computational Fluid Dynamic (CFD) simulation as a method to minimize the number of function evaluations and thereby obtain substantial reductions in computational time. Two optimization objectives were considered: a) maximizing heat density rate per temperature difference Q/(VΔT) and minimizing pumping power density (P/V), and b) maximizing base heat transfer coefficient (h) and minimizing pumping power per base area (P/Abase). Water and air were used as working fluids to compare the optimum solutions of the two fluids with very distinctive thermo-physical properties. The study shows that both optimization objectives result in similar optimum points. The behaviors of the optimum solutions for water and air are also discussed in detail. Additionally, as a case study using the optimization results, it was demonstrated that for an array of microchannels with volume as low as 4,250 mm3 on one side, pumping power of 138 W and heat transfer rate of 56.7 kW can be achieved using water.

An Air-Based Cavity-Receiver for Solar Trough Concentrators

2010 ◽  
Vol 132 (3) ◽  
Author(s):  
Roman Bader ◽  
Maurizio Barbato ◽  
Andrea Pedretti ◽  
Aldo Steinfeld
Keyword(s):  
Heat Transfer ◽  
Solar Power ◽  
Power Input ◽  
Absorption Efficiency ◽  
Conservation Equation ◽  
Heat Transfer Fluid ◽  
Inlet Temperature ◽  
Transfer Model ◽  
Pumping Power ◽  
Power Requirement

A cylindrical cavity-receiver containing a tubular absorber that uses air as the heat transfer fluid is proposed for a novel solar trough concentrator design. A numerical heat transfer model is developed to determine the receiver’s absorption efficiency and pumping power requirement. The 2D steady-state energy conservation equation coupling radiation, convection, and conduction heat transfer is formulated and solved numerically by finite volume techniques. The Monte Carlo ray-tracing and radiosity methods are applied to establish the solar radiation distribution and radiative exchange within the receiver. Simulations were conducted for a 50 m-long and 9.5 m-wide collector section with 120°C air inlet temperature, and air mass flows in the range 0.1–1.2 kg/s. Outlet air temperatures ranged from 260°C to 601°C, and corresponding absorption efficiencies varied between 60% and 18%. Main heat losses integrated over the receiver length were due to reflection and spillage at the receiver’s windowed aperture, amounting to 13% and 9% of the solar power input, respectively. The pressure drop along the 50 m module was in the range 0.23–11.84 mbars, resulting in isentropic pumping power requirements of 6.45×10−4−0.395% of the solar power input.

NUMERICAL INVESTIGATION OF CONJUGATE HEAT TRANSFER FROM LAMINAR WALL JET FLOW OVER A SHALLOW CAVITY

2018 ◽  
Vol 49 (12) ◽  
pp. 1151-1170 ◽  
Author(s):  
Maheandera Prabu Paulraj ◽  
Rajesh Kanna Parthasarathy ◽  
Jan Taler ◽  
Dawid Taler ◽  
Pawel Oclon ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Numerical Investigation ◽  
Conjugate Heat Transfer ◽  
Jet Flow ◽  
Wall Jet ◽  
Shallow Cavity ◽  
Wall Jet Flow
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