Optimization of Vortex Promoter Design Using a Dynamic Data Driven Approach

Author(s):  
Tunc Icoz ◽  
Yogesh Jaluria

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.

2006 ◽  
Vol 128 (10) ◽  
pp. 1081-1092 ◽  
Author(s):  
Tunc Icoz ◽  
Yogesh Jaluria

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.


Author(s):  
Debora C. Moreira ◽  
Gherhardt Ribatski ◽  
Satish G. Kandlikar

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.


Volume 4 ◽  
2004 ◽  
Author(s):  
T. Icoz ◽  
N. Verma ◽  
Y. Jaluria

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.


Author(s):  
Limin Wang ◽  
Yufan Bu ◽  
Xun Chen ◽  
Xiaoyang Wei ◽  
Dechao Li ◽  
...  

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.


Author(s):  
D. D. Ma ◽  
G. D. Xia ◽  
W. Wang ◽  
X. F. Li ◽  
Y. T. Jia

3D-IC is getting increasingly attractive, as it improves speed and frequency, and reduces power consumption, noise and latency. However, three dimension (3D) integration technologies bring a new serious challenge to chip thermal management with the power density increased exponentially. Interlayer microchannel liquid cooling is thought as a promising and scalable solution for cooling high heat flux 3D-IC. In this paper, firstly channel number, channel width and height parameters of rectangular channel are optimized by the method of multi-objective parameter optimization under given overall size of 5mm in length and 5mm in width. The results show the total thermal resistances can reach very small under individual constraint condition of volume flow rates, but the pressure drop is too larger to accept. The minimum thermal resistance structure can be got by multi-objective optimization at various constraint conditions. It is found that the channel height and width increase with increasing of flow rates at pumping power less than 0.1W and pressure drop less than 20kPa. Secondly, the zigzag channels are designed on the basis of the optimized rectangular channel structure. The expansion and contraction ratio as an important parameter is optimized by numerical simulation. The thermal enhancement factor and Nusselt number measure the comprehensive performances of heat transfer. The results show heat transfer characteristic is enhanced with the decreasing of expansion and contraction ratio. Besides, the maximum junction temperature and maximum temperature difference are also reduced. 3D-IC with wave channel of β=3/7 is more promising for interlayer cooling.


Author(s):  
José Luis ZUÑIGA-CERROBLANCO ◽  
Juan Gregorio HORTELANO-CAPETILLO ◽  
Juan Carlos COLLAZO-BARRIENTOS ◽  
Abel HERNANDEZ-GUERRERO

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.


1992 ◽  
Vol 114 (1) ◽  
pp. 14-21 ◽  
Author(s):  
Ann M. Anderson ◽  
Robert J. Moffat

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.


1992 ◽  
Vol 114 (1) ◽  
pp. 22-28 ◽  
Author(s):  
A. M. Anderson ◽  
R. J. Moffat

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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