Design, Development, and Characterization of a Flow Control Device for Dynamic Cooling of Liquid-Cooled Servers

2021 ◽  
Author(s):  
Pardeep Shahi ◽  
Apurv Deshmukh ◽  
Hardik Hurnekar ◽  
Satyam Saini ◽  
Pratik V Bansode ◽  
...  
Keyword(s):  
Thermal Management ◽  
Flow Rate ◽  
Control Device ◽  
Servo Motor ◽  
Pumping Power ◽  
Liquid Cooling ◽  
Flow Rates ◽  
Flow Control Device ◽  
Dynamic Cooling ◽  
Valve Position

Abstract Transistor density trends till recently have been following Moore's law, doubling every generation resulting in increased power density. The computational performance gains with the breakdown of Moore's law were achieved by using multi-core processors, leading to non-uniform power distribution and localized high temperatures making thermal management even more challenging. Cold plate-based liquid cooling has proven to be one of the most efficient technologies in overcoming these thermal management issues. Traditional liquid-cooled data center deployments provide a constant flow rate to servers irrespective of the workload, leading to excessive consumption of coolant pumping power. Therefore, a further enhancement in the efficiency of implementation of liquid cooling in data centers is possible. The present investigation proposes the implementation of dynamic cooling using an active flow control device to regulate the coolant flow rates at the server level. This device can aid in pumping power savings by controlling the flow rates based on server utilization. The FCD design contains a V-cut ball valve connected to a micro servo motor used for varying the device valve angle. The valve position was varied to change the flow rate through the valve by servo motor actuation based on pre-decided rotational angles. The device operation was characterized by quantifying the flow rates and pressure drop across the device by changing the valve position using both CFD and experiments. The proposed FCD was able to vary the flow rate between 0.09 lpm to 4 lpm at different valve positions.

Analysis and Optimization Design of Pressure Compensated Flow Control Valves

2003 ◽  
Author(s):  
Duqiang Wu ◽  
Richard Burton ◽  
Greg Schoenau ◽  
Doug Bitner
Keyword(s):  
Pressure Drop ◽  
Flow Control ◽  
Flow Rate ◽  
Total Pressure ◽  
Optimization Design ◽  
Constant Pressure ◽  
Control Device ◽  
Operating Conditions ◽  
Flow Control Device ◽  
Linearized Model

A pressure compensated valve (PC valve) is a type of flow control device that is a combination of a control orifice and a compensator (often called a hydrostat). The compensator orifice modulates its opening to maintain a constant pressure drop across the control orifice. In other words, the PC valve is so designed that the flow rate through the valve is governed only by the opening of the control orifice and is independent of the total pressure drop across the valve. Because of the high non-linearities associated with this type of valve, it is impossible, in practice, to design such a valve where the flow rate is completely unaffected by the pressure drop across the valve. In this paper, the effect of the non-linerities on the performance of the PC valve is investigated. First, a generic non-liner model of a PC valve is developed. Using this model, all possible operating conditions can be determined. Then a linearized model is developed and used to analyze the dynamic behavior of the PC valve. The model can then be used to optimize the design and operation of the valve for specific applications.

scholarly journals Optimization of Thermal Management System with Water and Phase Change Material Cooling for Li-Ion Battery Pack

Energies ◽  
2021 ◽  
Vol 14 (17) ◽  
pp. 5312
Author(s):  
Quanyi Li ◽  
Jong-Rae Cho ◽  
Jianguang Zhai
Keyword(s):  
Service Life ◽  
Thermal Management ◽  
Flow Rate ◽  
Battery Pack ◽  
Liquid Cooling ◽  
Cooling Performance ◽  
Cooling Pipe ◽  
Thermal Management System ◽  
Battery Packs ◽  
Change Material

The cooling structure of a battery pack and coupled liquid cooling and phase change material (PCM) were designed in a thermal management system to enhance the cooling performance and extend the service life of lithium-ion battery packs. Numerical simulations were conducted based on the finite volume method. This study focuses on factors such as the layout of the terminal, flow rate of the coolant, different sections of the cooling pipe, position of the cooling pipe, and coupled liquid cooling, and investigates their influences on the operating temperature. The results show that a reasonable terminal layout can reduce heat generation inside the batteries. The appropriate flow rate and position of the cooling pipe effectively reduced the maximum temperature and minimized energy consumption. Then, the PCM was placed between the adjacent batteries near the outlet to enhance the uniformity of the battery pack. The temperature difference was reduced to near 5 K. This study provides a clear direction for improving the cooling performance and extending the service life of battery packs.

Computational Study and Optimization of Laminar Heat Transfer and Pressure Loss of Double-Layer Microchannels for Chip Liquid Cooling

2013 ◽  
Vol 5 (1) ◽  
Author(s):  
Gongnan Xie ◽  
Yanquan Liu ◽  
Bengt Sunden ◽  
Weihong Zhang
Keyword(s):  
Heat Transfer ◽  
Pressure Drop ◽  
Double Layer ◽  
Flow Rate ◽  
Single Layer ◽  
Parallel Flow ◽  
Heat Fluxes ◽  
Liquid Cooling ◽  
Counter Flow ◽  
Flow Rates

The problem involved in the increase of the chip output power of high-performance integrated electronic devices is the failure of reliability because of excessive thermal loads. This requires advanced cooling methods to be incorporated to manage the increase of the dissipated heat. The traditional air-cooling can not meet the requirements of cooling heat fluxes as high as 100 W/cm2, or even higher, and the traditional liquid cooling is not sufficient either in cooling very high heat fluxes although the pressure drop is small. Therefore, a new generation of liquid cooling technology becomes necessary. Various microchannels are widely used to cool the electronic chips by a gas or liquid removing the heat, but these microchannels are often designed to be single-layer channels with high pressure drop. In this paper, the laminar heat transfer and pressure loss of a kind of double-layer microchannel have been investigated numerically. The layouts of parallel-flow and counter-flow for inlet/outlet flow directions are designed and then several sets of inlet flow rates are considered. The simulations show that such a double-layer microchannel can not only reduce the pressure drop effectively but also exhibits better thermal characteristics. Due to the negative heat flux effect, the parallel-flow layout is found to be better for heat dissipation when the flow rate is limited to a low value while the counter-flow layout is better when a high flow rate can be provided. In addition, the thermal performance of the single-layer microchannel is between those of parallel-flow layout and counter-flow layout of the double-layer microchannel at low flow rates. At last, the optimizations of geometry parameters of double-layer microchannel are carried out through changing the height of the upper-branch and lower-branch channels to investigate the influence on the thermal performance.

scholarly journals Multi-Physics Equivalent Circuit Models for a Cooling System of a Lithium Ion Battery Pack

Batteries ◽  
2020 ◽  
Vol 6 (3) ◽  
pp. 44 ◽  
Author(s):  
Takumi Yamanaka ◽  
Daiki Kihara ◽  
Yoichi Takagishi ◽  
Tatsuya Yamaue
Keyword(s):  
Heat Transfer ◽  
Equivalent Circuit ◽  
Thermal Management ◽  
Flow Rate ◽  
3D Model ◽  
Management Systems ◽  
Li Ion Battery ◽  
Liquid Cooling ◽  
Battery Packs ◽  
Li Ion

Lithium (Li)-ion battery thermal management systems play an important role in electric vehicles because the performance and lifespan of the batteries are affected by the battery temperature. This study proposes a framework to establish equivalent circuit models (ECMs) that can reproduce the multi-physics phenomenon of Li-ion battery packs, which includes liquid cooling systems with a unified method. We also demonstrate its utility by establishing an ECM of the thermal management systems of the actual battery packs. Experiments simulating the liquid cooling of a battery pack are performed, and a three-dimensional (3D) model is established. The 3D model reproduces the heat generated by the battery and the heat transfer to the coolant. The results of the 3D model agree well with the experimental data. Further, the relationship between the flow rate and pressure drop or between the flow rate and heat transfer coefficients is predicted with the 3D model, and the data are used for the ECM, which is established using MATLAB Simulink. This investigation confirmed that the ECM’s accuracy is as high as the 3D model even though its computational costs are 96% lower than the 3D model.

Fixed Valve Piezoelectric Micropump for Miniature Thermal Management Module

2006 ◽  
Author(s):  
D. Faulkner ◽  
C. Ward ◽  
D. Gilbuena ◽  
R. Shekarriz ◽  
F. K. Forster
Keyword(s):  
Thermal Management ◽  
Flow Rate ◽  
Maximum Flow ◽  
Liquid Cooling ◽  
Cavity Depth ◽  
Load Pressure ◽  
Photochemical Etching ◽  
Thermal Management System ◽  
Cooling Module ◽  
The Impact

In this paper, we discuss implementation of a micropump with fixed-geometry Tesla-type valves in a closed-loop forced convection thermal management system. The micropump was integrated with a heat sink in a stacked array and fabricated using a photochemical etching process. Two different micropump cavity diameters of 10-mm and 15-mm were fabricated and tested. For each cavity diameter, there were three valve sizes ranging from 140-μm to 340-μm in width. For the best-performing micropump we also evaluated the impact of varying the aspect ratio by adding and removing layers within the micropump. Our results indicated that as the diameter or cavity depth increased the performance of the pump in terms of block load pressure and flow rate degraded. Also, decreasing the valve width for each cavity diameter and height tended to increase the block load pressure and the resulting flow rate. For a pump with 140-μm valve width and an optimal cavity height of 550-μm (11-layers), the maximum flow and pressures obtained for a single pump subassembly were nearly 1.1-mL/min and 0.8-psi. A stack of 4 micropump subassemblies provided more than 5.5 mL/min flow rate and 0.5-psi pressure. The micropump power consumption was less than 50-mW per subassembly, and including the driving electronics power conversion, it consumed less than 0.5-W of power under these conditions. The thermal performance of an integrated liquid cooling module on standard Pentium P4 microprocessor running at up to 40-W was comparable to an off-the-shelf heatsink, but in a package less than 1/10 the size. This unit is currently being considered for blade server applications.

Improved Flow Rate in Electro-Osmotic Micropumps for Combinations of Substrates and Different Liquids With and Without Nanoparticles

2015 ◽  
Vol 137 (2) ◽  
Author(s):  
Marwan F. Al-Rjoub ◽  
Ajit K. Roy ◽  
Sabyasachi Ganguli ◽  
Rupak K. Banerjee
Keyword(s):  
Heat Transfer ◽  
Zeta Potential ◽  
Thermal Management ◽  
Flow Rate ◽  
Maximum Flow ◽  
Enhanced Heat Transfer ◽  
Flow Rates ◽  
Current Leakage ◽  
Different Types ◽  
Electro Osmotic Flow

A new design for an electro-osmotic flow (EOF) driven micropump was fabricated. Considering thermal management applications, three different types of micropumps were tested using multiple liquids. The micropumps were fabricated from a combination of materials, which included: silicon-polydimethylsiloxane (Si-PDMS), Glass-PDMS, or PDMS-PDMS. The flow rates of the micropumps were experimentally and numerically assessed. Different combinations of materials and liquids resulted in variable values of zeta-potential. The ranges of zeta-potential for Si-PDMS, Glass-PDMS, and PDMS-PDMS were −42.5–−50.7 mV, −76.0–−88.2 mV, and −76.0–−103.0 mV, respectively. The flow rates of the micropumps were proportional to their zeta-potential values. In particular, flow rate values were found to be linearly proportional to the applied voltages below 500 V. A maximum flow rate of 75.9 μL/min was achieved for the Glass-PDMS micropump at 1 kV. At higher voltages nonlinearity and reduction in flow rate occurred due to Joule heating and the axial electro-osmotic current leakage through the silicon substrate. The fabricated micropumps could deliver flow rates, which were orders of magnitude higher compared to the previously reported values for similar size micropumps. It is expected that such an increase in flow rate, particularly in the case of the Si-PDMS micropump, would lead to enhanced heat transfer for microchip cooling applications as well as for applications involving micrototal analysis systems (μTAS).

Analysis of a Pressure-Compensated Flow Control Valve

2004 ◽  
Vol 129 (2) ◽  
pp. 203-211 ◽  
Author(s):  
D. Wu ◽  
R. Burton ◽  
G. Schoenau ◽  
D. Bitner
Keyword(s):  
Pressure Drop ◽  
Flow Control ◽  
Flow Rate ◽  
Constant Pressure ◽  
Control Valve ◽  
Control Device ◽  
Operating Conditions ◽  
Flow Control Valve ◽  
Flow Control Device ◽  
Linearized Model

A pressure-compensated valve (PC valve) is a type of flow control device that is a combination of a control orifice and a compensator (often called a hydrostat). The compensator orifice modulates its opening to maintain a constant pressure drop across the control orifice. In other words, the PC valve is so designed that the flow rate through the valve is governed only by the opening of the control orifice and is independent of the total pressure drop across the valve. Because of the high nonlinearities associated with this type of valve, it is impossible, in practice, to design such a valve where the flow rate is completely unaffected by the pressure drop across the valve. In this paper, the effect of the nonlinearities on the performance of the PC valve is investigated. First, a generic nonlinear model of a PC valve is developed. Using this model, all possible operating conditions can be determined. Then a linearized model is developed and used to analyze the dynamic behavior of the PC valve. The model can then be used to evaluate and improve the design and operation of the valve for specific applications.

Characteristic Study on the Optimization of Pin-Fin Micro Heat Sink

2009 ◽  
Author(s):  
T. J. John ◽  
B. Mathew ◽  
H. Hegab
Keyword(s):  
Pressure Drop ◽  
Thermal Resistance ◽  
Flow Rate ◽  
Heat Sink ◽  
Heat Dissipation ◽  
Heat Sinks ◽  
Low Flow ◽  
Pumping Power ◽  
Flow Rates ◽  
Pin Fin

The need for dissipating heat from microsystems has increased drastically in the last decade. Several methods of heat dissipation using air and liquids have been proposed by many studies, and pin-fin micro heat sinks are one among them. Researchers have developed several effective pin-fin structures for use in heat sinks, but not much effort has been taken towards the optimization of profile and dimensions of the pin-fin. In this paper the authors studied the effect of different pin-fin shapes on the thermal resistance and pressure drop in a specific micro heat-sink. Optimization subjected to two different constraints is studied in this paper. The first optimization is subjected to constant flow rate and the second one is subjected to constant pressure drop. Both optimization processes are carried out using computer simulations generated using COVENTORWARE™. Two of the best structures from each of these optimization studies are selected and further analysis is performed for optimizing their structure dimensions such as width, height and length. A section of the total micro heat-sink is modeled for the initial optimization of the pin-fin shape. The model consists of two sections, the substrate and the fluid. Six different shapes: square, circle, rectangle, triangle, oval and rhombus were analyzed in the initial optimization study. Preliminary tests were conducted using the first model described above for a flow rate of 0.6ml/min. The non dimensional overall thermal resistance of the heat sink, and the nondimensional pumping power was calculated from the results. A figure of merit (FOM) was developed using the nondimensional thermal resistance and nondimensional pumping power for each structure with different pin-fin shapes. Smaller the value of FOM better the performance of the heat sink. The study revealed that the circle and ellipse structures have the best performance and the rectangle structure had the worst performance at low flow rates. At high flow rates rectangular and square structures have the best performance.

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