Design and Analysis: Thermal Emulator Cubes for Opto-Electronic Stacked Processor

2002 ◽  
Vol 124 (3) ◽  
pp. 198-204 ◽  
Author(s):  
Shiva P. Gadag ◽  
Susan K. Patra ◽  
Volkan Ozguz ◽  
Phillipe Marchand ◽  
Sadik Esener

3D finite element modeling of thermal emulator cube and its composition consisting of composite stack of multi-layer chip are developed. Thermal analysis of the Multi-Chip Module consisting of 16 alternate layers Si processor and heat sink layers with Si spacers and AlN ceramic cap is undertaken. The various alternatives for design of the emulator cubes such as thermal cube floating in free-space, thermal cube-on-substrate, thermal cube-on-flex cable with a continuous joint of solder and thermal cube embedded in rectangular Si-spacer are investigated for their heat extraction capability. Thermal modeling of a composite structural unit stack of chip offers first hand information as to the operating performance of the entire thermal emulator cube to be used in the construction of buffer cube. The scientific understanding of the mode of heat transfer of the emulator cube, heat extraction of the various heat sink materials, ceramic and the metallic substrates are investigated. A thin sheet of ceramic (AlN) substrate is at least three times more effective in extraction of heat than thick block of steel under similar conditions. The homogeneous and heterogeneous nature of the composite structure of thermal emulator in heat transfer is analyzed. The primary and secondary hotspots in thermal cubes with AlN heat sink are found in thermal simulations. The mode of heat transfer advances normal to lateral and transverse directions of stacking from the central core of the cube towards the outward face. The sharp corners of the cube typically exhibit edge convection due to chilling effect. Buffer-on-flex cable is modeled with a continuous solder joint and its further improvement with alternate hinges of solder joints and micro-channels is proposed for enhanced heat transfer analysis. The embedded emulator cubes are developed for thermal analysis of the optical layers on top of buffer. The optical layers with an interconnection of solder joints on top of the embedded emulator cubes coupled with micro-channels and hinged solder joints will be used for further enhanced heat transfer and higher dissipation of heat 1∼3W/layer resulting in efficient and cost effective thermal management technique.

Author(s):  
Satbir S. Sehgal ◽  
Krishnan Murugesan ◽  
S. K. Mohapatra

The advancements in fabricating and utilizing microchannel heat sinks (MCHS) for cooling of electronic devices during the last decade has not been matched by corresponding advances in our fundamental understanding of the unconventional micro fluidics. Many theoretical and experimental studies have been reported for the heat transfer analysis along the direction of flow within the microchannels, but to the best knowledge of the authors, the effect of the size of the inlet and outlet plenum and direction of the flow to the plenums was not studied exhaustively till date. The liquid is supplied to the microchannels via the inlet and outlet plenums and this can be achieved by many flow arrangements. Due to the small size of the channel dimensions, the entrance and exit conditions will significantly affect the heat transfer characteristics of the flow field in the channel. Instability effects at the entrance and exit regions of the micro-channel also need to be fully understood for efficient design of microchannel heat sinks. This paper presents an experimental study that has been conducted to explore the effect of entrance & exit conditions of the liquid flow within a copper micro-channel heat sink (MCHS). Three test pieces having inlet & outlet plenum dimensions of 8mm × 30mm, 10mm × 30 mm and 12 mm × 30 mm each with constant depth of 2.5 mm have been selected. Three different flow arrangements (U-Type, S-type and P-type) are studied for each test piece resulting in total nine flow arrangements. Each micro-channel heat sink contains an array of micro-channels in parallel having individual width of 330μm and channel depth of 2.5 mm. A comparison is made based on thermohydraulic performance of MCHS for different flow conditions at inlet and outlet plenums maintaining constant heat flux. Deionised water has been used in the experiments for the Reynolds number ranging from approximately 220 to 1100. The results are interpreted based on pressure drops and maximum temperature variations for these nine flow arrangements. Tests has been conducted to look for optimized dimensions and flow conditions at inlet and outlet plenums for the given fixed length of microchannels under same conjugate heat transfer conditions. Evaluations of experimental uncertainties have been meticulously made while selecting the instruments used in the experimental facility.


Author(s):  
Taiho Yeom ◽  
Terrence Simon ◽  
Tao Zhang ◽  
Min Zhang ◽  
Mark North ◽  
...  

Author(s):  
Liang-Han Chien ◽  
Han-Yang Liu ◽  
Wun-Rong Liao

A heat sink integrating micro-channels with multiple jets was designed to achieve better heat transfer performance for chip cooling. Dielectric fluid FC-72 was the working fluid. The heat sink contained 11 micro-channels, and each channel was 0.8 mm high, 0.6 mm wide, and 12 mm in length. There were 3 or 5 pores on each micro-channel. The pore diameters were either 0.24 or 0.4 mm, and the pore spacing ranged from 1.5 to 3 mm. In the tests, the saturation temperature of cooling device was set at 30 and 50°C, and the volume flow rate ranged from 9.1 to 73.6 ml/min per channel (total flow rate = 100∼810 ml/min). The experimental result showed that heat transfer performance increased with increasing flow rate for single phase heat transfer. For heat flux between 20 and 100 kW/m2, the wall superheat decreases with increasing flow rate at a fixed heat flux. However, the influence of the flow rate diminished when the channels are in two phase heat transfer regime. Except for the lowest flow rate (9.1 ml/min), the heat transfer performance increased with increasing jet diameter/spacing ratios. The best surface had three nozzles of 0.4 mm diameter in 3.0 mm jet spacing. It had the lowest thermal resistance of 0.0611 K / W in the range of 200 ∼ 240 W heat input.


2015 ◽  
Vol 3 (1) ◽  
pp. 12-20
Author(s):  
Yen-Tso Chang ◽  
Han-Ching Lin ◽  
Chi-Jui Huang ◽  
Chun-Hsien Chen ◽  
Chien-Jen Lin ◽  
...  

2019 ◽  
Vol 55 (8) ◽  
pp. 2247-2260 ◽  
Author(s):  
Ayush Gupta ◽  
Manoj Kumar ◽  
Anil Kumar Patil

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