Design Optimization of Size and Geometry of Vortex Promoter in a Two-Dimensional Channel

2006 ◽  
Vol 128 (10) ◽  
pp. 1081-1092 ◽  
Author(s):  
Tunc Icoz ◽  
Yogesh Jaluria
Keyword(s):  
Heat Transfer ◽  
Pressure Drop ◽  
Design Optimization ◽  
Computational Cost ◽  
Low Flow ◽  
Weighted Sums ◽  
Cooling Systems ◽  
Technical Problems ◽  
Concurrent Use ◽  
Simulation And Experiment

Thermal management of electronic equipment is one of the major technical problems in the development of electronic systems that would meet increasing future demands for speed and reliability. It is necessary to design cooling systems for removing the heat dissipated by the electronic components efficiently and with minimal cost. Vortex promoters have important implications in cooling systems for electronic devices, since these are used to enhance heat transfer from the heating elements. In this paper, an application of dynamic data driven optimization methodology, which employs concurrent use of simulation and experiment, is presented for the design of the vortex promoter to maximize the heat removal rate from multiple protruding heat sources located in a channel, while keeping the pressure drop within reasonable limits. Concurrent use of computer simulation and experiment in real time is shown to be an effective tool for efficient engineering design and optimization. Numerical simulation can effectively be used for low flow rates and low heat inputs. However, with transition to oscillatory and turbulent flows at large values of these quantities, the problem becomes more involved and computational cost increases dramatically. Under these circumstances, experimental systems are used to determine the component temperatures for varying heat input and flow conditions. The design variables are taken as the Reynolds number and the shape and size of the vortex promoter. The problem is a multiobjective design optimization problem, where the objectives are maximizing the total heat transfer rate Q and minimizing the pressure drop ΔP. This multiobjective problem is converted to a single-objective problem by combining the two objective functions in the form of weighted sums.

Optimization of Vortex Promoter Design Using a Dynamic Data Driven Approach

2005 ◽  
Author(s):  
Tunc Icoz ◽  
Yogesh Jaluria
Keyword(s):  
Heat Transfer ◽  
Pressure Drop ◽  
Data Driven ◽  
Low Flow ◽  
Cooling Systems ◽  
Dynamic Data ◽  
Technical Problems ◽  
Multi Objective ◽  
Concurrent Use ◽  
Simulation And Experiment

Thermal management of electronic equipment is one of the major technical problems in the development of electronic systems that would meet increasing future demands for speed and reliability. It is necessary to design cooling systems for removing the heat dissipated by the electronic components efficiently and with minimal cost. Vortex promoters have important implications in cooling systems for electronic devices, since these are used to enhance heat transfer from the heating elements. In this paper, an application of Dynamic Data Driven Optimization Methodology (DDDOM), which employs concurrent use of simulation and experiment, is presented for the design of the vortex promoter to maximize the heat removal rate from multiple protruding heat sources located in a channel, while keeping the pressure drop within reasonable limits. Concurrent use of computer simulation and experiment in real time is shown to be an effective tool for efficient engineering design and optimization. Numerical simulation can effectively be used for low flow rates and low heat inputs. However, with transition to oscillatory and turbulent flow at large values of these quantities, the problem becomes more involved and computational cost increases dramatically. Under these circumstances, experimental systems are used to determine the component temperatures for varying heat input and flow conditions. The design variables are taken as the Reynolds number and the shape and size of the vortex promoter. The problem is a multi-objective design optimization problem, where the objectives are maximizing the total heat transfer rate, as given by the Nusselt number, Nu, and minimizing the pressure drop, ΔP. This multi–objective problem is converted to a single-objective problem by combining the two objective functions of the form Nutota/ΔPb, where a and b are constants.

scholarly journals A MCDM Methodology to Determine the Most Critical Variables in the Pressure Drop and Heat Transfer in Minichannels

Energies ◽  
2021 ◽  
Vol 14 (8) ◽  
pp. 2069
Author(s):  
Eloy Hontoria ◽  
Alejandro López-Belchí ◽  
Nolberto Munier ◽  
Francisco Vera-García
Keyword(s):  
Heat Transfer ◽  
Pressure Drop ◽  
Heat Exchangers ◽  
Saturation Pressure ◽  
Computational Cost ◽  
Urban Systems ◽  
Condensation Process ◽  
Geometrical Parameters ◽  
Maximum Heat ◽  
Maximum Heat Transfer

This paper proposes a methodology aiming at determining the most influent working variables and geometrical parameters over the pressure drop and heat transfer during the condensation process of several refrigerant gases using heat exchangers with pipes mini channels technology. A multi-criteria decision making (MCDM) methodology was used; this MCDM includes a mathematical method called SIMUS (Sequential Interactive Modelling for Urban Systems) that was applied to the results of 2543 tests obtained by using a designed refrigeration rig in which five different refrigerants (R32, R134a, R290, R410A and R1234yf) and two different tube geometries were tested. This methodology allows us to reduce the computational cost compared to the use of neural networks or other model development systems. This research shows six variables out of 39 that better define simultaneously the minimum pressure drop, as well as the maximum heat transfer, saturation pressure fluid entering the condenser being the most important one. Another aim of this research was to highlight a new methodology based on operation research for their application to improve the heat transfer energy efficiency and reduce the CO2 footprint derived of the use of heat exchangers with minichannels.

Effects of Taper Configurations on Heat Transfer and Pressure Drop in Single-Phase Flows in Microgaps

2020 ◽  
Author(s):  
Debora C. Moreira ◽  
Gherhardt Ribatski ◽  
Satish G. Kandlikar
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Pressure Drop ◽  
Single Phase ◽  
Bubble Nucleation ◽  
Low Flow ◽  
Working Fluid ◽  
Inlet Temperature ◽  
Inlet Section ◽  
Flow Rates

Abstract This paper presents a comparison of heat transfer and pressure drop during single-phase flows inside diverging, converging, and uniform microgaps using distilled water as the working fluid. The microgaps were created on a plain heated copper surface with a polysulfone cover that was either uniform or tapered with an angle of 3.4°. The average gap height was 400 microns and the length and width dimensions were 10 mm × 10 mm, resulting in an average hydraulic diameter of approximately 800 microns for all configurations. Experiments were conducted at atmospheric pressure and the inlet temperature was set to 30 °C. Heat transfer and pressure drop data were acquired for flow rates varying from 57 to 485 ml/min and the surface temperature was monitored not to exceed 90 °C to avoid bubble nucleation, so the heat flux varied from 35 to 153 W/cm2 depending on the flow rate. The uniform configuration resulted in the lowest pressure drop, and the diverging one showed slightly higher pressure drop values than the converging configuration, possibly because the flow is most constrained at the inlet section, where the fluid is colder and presents higher viscosity. In addition, a minor dependence of pressure drop with heat flux was observed due to temperature dependent properties. The best heat transfer performance was obtained with the converging configuration, which was especially significant at low flow rates. This behavior could be explained by an increase in the heat transfer coefficient due to flow acceleration in converging gaps, which compensates the decrease in temperature difference between the fluid and the surface due to fluid heating along the gap. Overall, the comparison between the three configurations shows that converging microgaps have better performance than uniform or diverging ones for single-phase flows, and such effect is more pronounced at lower flow rates, when the fluid experiences higher temperature changes.

Design of Air and Liquid Cooling Systems for Electronic Components Using Concurrent Simulation and Experiment

Volume 4 ◽  
2004 ◽  
Author(s):  
T. Icoz ◽  
N. Verma ◽  
Y. Jaluria
Keyword(s):  
Heat Transfer ◽  
The Other ◽  
Simple Problem ◽  
Electronic Systems ◽  
Efficient Design ◽  
Electronic Components ◽  
Liquid Cooling ◽  
Cooling Systems ◽  
Simulation And Experiment ◽  
Concurrent Simulation

The design of cooling systems for electronic equipment is getting more involved and challenging due to increase in demand for faster and more reliable electronic systems. Therefore, robust and more efficient design and optimization methodologies are required. Conventional approaches are based on sequential use of numerical simulation and experiment. Thus, they fail to use certain advantages of using both tools concurrently. The present study is aimed at combining simulation and experiment in a concurrent manner such that outputs of each approach drives the other to achieve better engineering design in a more efficient way. In this study, a relatively simple problem involving heat transfer from multiple heat sources, simulating electronic components, located in a horizontal channel was investigated experimentally and numerically. Two experimental setups were fabricated for air and liquid cooling experiments to study the effects of different coolants. De-ionized water was used as the liquid coolant in one case and air in the other. The effects of separation distance and flow conditions on the heat transfer and fluid flow characteristics were investigated in details for both coolants. Cooling capabilities of different cooling arrangements were compared and the results from simulations and experiments were combined to provide quantitative inputs for the design. The domains over which experimental or the numerical approach is superior to the other are determined. Simulations are used to guide the experiments and vice versa. It is found that the proposed optimization methodology can be implemented in the design of cooling systems for electronic components for faster and more efficient convergence. This methodology can also be extended to more complex and practical electronic systems.

Multi-Objective Design Optimization of Rotating Regenerative Air Preheater Using Genetic Algorithm

2018 ◽  
Author(s):  
Limin Wang ◽  
Yufan Bu ◽  
Xun Chen ◽  
Xiaoyang Wei ◽  
Dechao Li ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Genetic Algorithm ◽  
Pressure Drop ◽  
Design Optimization ◽  
Hydraulic Calculation ◽  
Maximum Heat ◽  
Multi Objective ◽  
Upper Limit ◽  
Maximum Heat Transfer ◽  
Conflicting Objectives

In previous references, no study has been done on the optimization of rotary regenerative air preheaters (RAPHs) used in coal-fired power plants yet. The key structure parameters of RAPH include rotor radius, fluid section angles and matrix layer heights. In this study, work on the multi-objective design optimization of an RAPH was conducted by combing the thermal hydraulic calculation program which is developed to calculate the temperature and the pressure drop and the non-dominated sorting genetic algorithm (NSGA-II). The maximum heat transfer rate and the minimum friction, namely minimum outlet gas temperature and pressure drop, are considered as the conflicting objectives in the multi-optimization. The layer heights, rotor radius, angles of fluid sections and heights of matrix layers are involved in the design variables in the optimization. The optimization includes three cases in which the rotor radius upper limits are 7 m, 8 m and 9 m respectively. Sets of the Pareto-optimal front points were obtained for the different cases. The obtained optimal air-preheaters with larger upper limit of rotor radius would have better Pareto results. The optimum rotor radius is the upper limit value for different design range of rotor radius. The air-preheaters with larger upper design limit of rotor radius would have better Pareto results. In other words, if the upper design limit of rotor radius is too small, all the Pareto points in this case could not satisfy the performance requirements of heat transfer and friction, and the only way is to increase the upper design limit of rotor radius. The ratio of each optimum fluid section angle is determined by the fluid flow rate of each section.

Numerical Simulation of Advanced Monolithic Microcooler Designs for High Heat Flux Microelectronics

2015 ◽  
Author(s):  
Sebastian Scholl ◽  
Catherine Gorle ◽  
Farzad Houshmand ◽  
Tanya Liu ◽  
Hyoungsoon Lee ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Pressure Drop ◽  
Transfer Coefficient ◽  
Mass Flow ◽  
Heat Sink ◽  
Conjugate Heat Transfer ◽  
Computational Cost ◽  
Unit Cell ◽  
Micro Structure

This study considers CFD simulations with conjugate heat transfer performed in the framework of designing a complex micro-scale cooling geometry. The numerical investigation of the three-dimensional, laminar flow (Reynolds number smaller than 480) and the solid conduction is done on a reduced model of the heat sink micro-structure to enable exploring a variety of configurations at a limited computational cost. The reduced model represents a unit-cell, and uses periodic and symmetry boundary conditions to mimic the conditions in the entire cooling manifold. A simulation of the entire heat sink micro-structure was performed to verify the unit-cell set-up, and the comparison demonstrated that the unit-cell simulations allow reducing the computational cost by two orders of magnitude while retaining accurate results. The baseline design for the unit-cell represents a configuration used in traditional electronic heat sinks, i.e. a simple channel geometry with a rectangular cross section, with a diameter of 50 μm, where the fluid flows between two cooling fins. Subsequently three types of modified geometries with feature sizes of 50 μm were considered: baffled geometries that guide the flow towards the hotspot region, geometries where the fins are connected by crossbars, and a woodpile structure without cooling fins. Three different mass-flow rates were tested. Based on the medium mass-flow rate considered, the woodpile geometry showed the highest heat transfer coefficient with an increase of 70% compared to the baseline geometry, but at the cost of increasing the pressure drop by more than 300%. The crossbar geometries were shown to be promising configurations, with increases in the heat transfer coefficient of more than 20% for a 70% increase in pressure drop. The potential for further optimization of the crossbar configurations by adding or removing individual crossbars will be investigated in a follow up study. The results presented demonstrate the increase in performance that can be obtained by investigating a variety of designs for single phase cooling devices using unit-cell conjugate heat transfer simulations.

scholarly journals Análisis térmico e hidráulico de diferentes geometrías de tubos para mejorar el desempeño de un radiador de automóvil

2020 ◽  
pp. 13-23
Author(s):  
José Luis ZUÑIGA-CERROBLANCO ◽  
Juan Gregorio HORTELANO-CAPETILLO ◽  
Juan Carlos COLLAZO-BARRIENTOS ◽  
Abel HERNANDEZ-GUERRERO
Keyword(s):  
Heat Transfer ◽  
Pressure Drop ◽  
Automotive Industry ◽  
New Technologies ◽  
Cooling System ◽  
Numerical Study ◽  
Hydraulic Performance ◽  
Cooling Systems ◽  
Cooling Fluid ◽  
Nusselt Numbers

Nowadays the automotive industry requires more powerful and compact engines, which demand that the cooling systems must be improved using new technologies to attend the aim to maintain the engine working at optimum temperature, the cooling system must be adjusted to the dimensions and weight set to avoid the increase of fuel expense. In the present work a numerical study to analyze the thermal and hydraulic performance of a car radiator is carried out. The research focuses on analyzing different geometries for the tubes that make up the radiator, inside of tubes a mixture of 80% water and 20% ethylene glycol is used as the cooling fluid. On the results the global Nusselt numbers for the different geometries, as well as the total pressure drop along the radiator tube are reported. A comparison of the thermal and hydraulic performance for the different geometries analyzed is made. From the results the best geometry to increase heat transfer is chosen, as well as the geometry with the best balance between entropy generation due to heat transfer and pressure drop is chosen.

The Adiabatic Heat Transfer Coefficient and the Superposition Kernel Function: Part 1—Data for Arrays of Flatpacks for Different Flow Conditions

1992 ◽  
Vol 114 (1) ◽  
pp. 14-21 ◽  
Author(s):  
Ann M. Anderson ◽  
Robert J. Moffat
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Pressure Drop ◽  
Transfer Coefficient ◽  
Convection Heat Transfer ◽  
Kernel Functions ◽  
Flow Conditions ◽  
Technical Problems ◽  
Line Array ◽  
Transfer Problems

This paper describes an investigation of the forced convection heat transfer and pressure drop characteristics of a regular in-line array of flatpacks for several channel heights and inlet velocities. The work has both practical and theoretical interest since it relates to technical problems now faced by the electronics industry, and it embodies one of the most general heat transfer problems: non-uniform heat release from nonuniform geometries. To predict operating temperatures in situations where the wall temperature distribution is non-uniform, one must use superposition. Both the adiabatic heat transfer coefficient, had, and the superposition kernel functions, g*, are required. The problem can be solved using superposition directly (had and g*) or indirectly (using had and g* to calculate the correct value of hm). Either way the superposition data is required. This work presents the first full set of superposition data for flatpack arrays. Part 1 presents heat transfer and pressure drop results and part 2 presents a model for heat transfer that is based on the maximum turbulence fluctuations in the channel.

Multi-Objective Design Optimization of Multiple Microchannel Heat Transfer Systems Based on Multiple Prioritized Preferences

2017 ◽  
Vol 9 (2) ◽  
Author(s):  
Po Ting Lin ◽  
Mark Christian E. Manuel ◽  
Jingru Zhang ◽  
Yogesh Jaluria ◽  
Hae Chang Gea
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Optimal Design ◽  
Pressure Drop ◽  
Design Optimization ◽  
Integrated Circuit ◽  
Pareto Frontier ◽  
User Preferences ◽  
Optimization Strategy ◽  
Design Variables

Accelerated development in the field of electronics and integrated circuit technology further pushed the need for better heat dissipating devices with reduced component dimensions. In the design optimization of microchannel heat transfer systems, multiple objectives must be satisfied but correlations limit the satisfaction levels. End users define their preferences associated with the desired quality/quantity of each parameter and specify the priorities among each preference. In this paper, an optimization strategy based on the prioritized performances is developed to find the optimal design variables for the preferences in three different aspects namely: minimized thermal resistances, minimized pressure drop, and maximized heat flux. The preferences are often fuzzy and correlated but can be modeled mathematically using Gaussian membership functions with respect to different levels of user preferences. The overall performances are maximized to find the most favorable solution on the Pareto frontier. Two different types of single-phase liquid cooling (straight and U-shaped microchannel heat sinks) have been utilized as heat exchangers of electronic chips and made as practical examples for the proposed optimization strategy. The optimal design points vary with respect to the priorities of the preferences. The proposed methodology finds the most favored solution on the Pareto frontiers. It is novel to reveal that the chosen significant factors were maximized with results yielding to lower thermal resistance, lower pressure drop, and higher heat flux in the microchannel heat sink based on the design preferences with different priorities.

The Adiabatic Heat Transfer Coefficient and the Superposition Kernel Function: Part 2—Modeling Flatpack Data as a Function of Channel Turbulence

1992 ◽  
Vol 114 (1) ◽  
pp. 22-28 ◽  
Author(s):  
A. M. Anderson ◽  
R. J. Moffat
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Pressure Drop ◽  
Transfer Coefficient ◽  
Convection Heat Transfer ◽  
Electronics Industry ◽  
Kernel Functions ◽  
Technical Problems ◽  
Line Array ◽  
Transfer Problems

This paper describes an investigation of the forced convection heat transfer and pressure drop characteristics of a regular in-line array of flatpacks for several channel heights and inlet velocities. The work has both practical and theoretical interest since it relates to technical problems now faced by the electronics industry, and it embodies one of the most general heat transfer problems: nonuniform heat release from nonuniform geometries. To predict operating temperatures in situations where the wall temperature distribution is nonuniform, one must use superposition. Both the adiabatic heat transfer coefficient, had and the superposition kernel functions, g* are required. The problem can be solved using superposition directly (had and g*) or indirectly (using had and g* to calculate the correct value of hm). Either way the superposition data is required. This work presents the first full set of superposition data for flatpack arrays. Part 1 presents heat transfer and pressure drop results and part 2 presents a model for heat transfer that is based on the maximum turbulence fluctuations in the channel.

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