Water-cooled radiator design and optimization research for high power 3D-Sip system encapsulate

For high power package water-cooled radiator of 3D-Sip system and by using the finite element software ANSYS numerical simulation analysis of the geometrical parameters and fluid velocity affecting the performance of radiator cooling, the condition of air cooling water-cooled radiator fin thickness, spacing, and affect the performance of water cooled radiator cooling fluid flow curve is received. At the same time, water-cooled radiator outlet temperature of the inlet pressure and multi-objective optimization is based on the Pareto genetic algorithm. The results for high power 3D-Sip the design and system package of water-cooled radiator provides a certain basis. Introduction As the miniaturization of high power circuit module and the bad using environment, the cooling performance of they need stronger and stronger. The efficiency of forced water cooling is 20 times than the traditional cooling, it is a kind of good thermal design solutions[1]. According to the International Technology Roadmap for Semiconductors, single-chip power density of a high-performance system is expected to be higher than 100W/cm2[2]. In this paper, water cooling radiator for a specific high-power 3D-Sip (three-dimensional system in package) structure design, numerical simulation using ANSYS finite element techniques to analyze fluid flow, structural parameters of the cooling fins affect the fluid outlet temperature, at last based on genetic PARETO algorithms for fluid outlet temperature and fluid inlet pressure for multi-objective optimization, provide a reference for the design and optimization of high-power 3D-Sip water-cooled radiator system packaging. Problem description and model establishment 2.1 Problem description In this paper, a high power 3D-Sip packaging system for the design of water-cooled radiator, 15 C temperature drop was required. Referring to the technology of electronic radiator manual, it is assumed that the temperature of water inlet is 50 C, the initial size of outline dimension of water-cooled radiator is 44 x 44 x 10 (mm), in which the height of the heat dissipation fin is 8 mm, water cavity is cubic and the size is 40 * 40 * 1.2 (mm), the outlet and the nozzle aperture is 0.8 mm, fin thickness is 1.5 mm, fin spacing is 3 mm, the initial velocity of water on the entrance is 0.01 m/s, its physical parameters as shown in table 1. Table 1: Material parameters Material density (kg/m) conductivity (w/m·k) Specific heat (J/kg·k) viscosity(m2/s) Al 2880 240 90.64 ── Cooling medium 997 0.613 4179 8.55e-4 2.2 The establishment of simulation mode ANSYS is a large general finite element analysis software which gather structure, thermal, fluid, International Conference on Information Sciences, Machinery, Materials and Energy (ICISMME 2015) © 2015. The authors Published by Atlantis Press 1446 magnetic, acoustic physical fields at an organic whole, and it provides most of the CAD software interface, realizes data sharing and exchanging, but also provides the user with ANSYS as a platform for the development of a variety of tools [3]. The model as shown in figure 1: this model to do the following assumptions: (1) set to turbulent flow, turbulence model judged by the Reynolds number Re = μ ρ / vDh , by Re < 2300 for laminar flow, instead of turbulence; ρ is the medium density (kg/m3), v is the fluid velocity (m/s); μ is the medium viscosity (pa, s);D is the water diameter [4]. (2) the fluid is incompressible. (3) fluid and the flow of material parameters are constants. (4) the passage wall is smooth, and its thermal resistance is ignored. (5) all wall without sliding speed (zero). (6) only considers heat convection and heat conduction, the thermal radiation is ignored. Fig.1: Water-cooled radiator simulation model 2.3 The simulation results Post-processing by ANSYS simulation is showed in figure 2 and figure 3 results: the lowest temperature at the outlet T = 33.51 C, entrance maximum pressure P = 1.117 Pa. Fig.2: Water-cooled radiator temperature distribution Fig.3: Water-cooled radiator pressure profile 3. The analysis of the water-cooled radiator fluid outlet temperature Heat conduction and thermal convection is the main mode for water-cooled radiator heat transfer, the inlet velocity of fluid and air convection finned shapes are the important factors influencing the water cooled radiator. Under the condition of the inlet temperature must, the system heat dissipation effect is reflected directly by fluid outlet temperature. The structure of inlet velocity and fin parameters on the influence law of exit temperature is analyzed in this paper. 3.1 The influence of outlet temperature by inlet velocity of fluid Air convection coefficient is generally constant, and the air forced convection is commonly 20 ~ 100 w/(m2 · k). On account of the environment of the forced air cooling, the value of 50 w/(m2 · k) is selected. environment temperature is setting value 25 C, the inlet temperature is setting value 50 C and outlet pressure is setting value 0Pa. the equivalent inlet flow rate of inlet velocity and 6 kinds