Pressure drop analysis of direct liquid cooled (DLC) rack
Pressure drop analysis of direct liquid cooled (DLC) rack
复制标题
DOI：
10.1109/itherm.2017.7992570
复制
发表时间：
2017-05
期刊：
影响因子：
--
通讯作者：
S. Alkharabsheh;Bharath Ramakrishnan;B. Sammakia
中科院分区：
文献类型：
--
作者：
S. Alkharabsheh;Bharath Ramakrishnan;B. Sammakia
本研究提出了一个实验和数值表征的压力降在商业上可用的直接液体冷却（DLC）机架。研究DLC系统中的压降非常重要，因为它决定了DLC系统所需的泵送功率，这会影响数据中心的能源效率。本研究的主要目的是评估流量和压力分布在DLC系统，以提高可靠性和冷却系统的效率。本研究的其他目标是评估流网络建模（FNM）在预测DLC机架中的流量分布方面的准确性，并确定可能影响冷却系统可靠性的商业系统中的制造限制。所研究的DLC系统的主要部件是：冷却剂分配模块（CDM）、供应/返回歧管模块和包含冷板的服务器模块。进行了大量的实验测量，以研究流量分布，并确定服务器模块和冷却剂分配模块（CDM）的压力特性曲线。此外，一种方法被描述为开发一个实验验证的流动网络模型（FNM）的DLC系统，以获得高精度。测试结果表明，微通道冷板的制造工艺导致了服务器模块间的流量分布不均。使用FNM预测服务器模块和CDM的流量的平均误差分别为2.5%和3.8%。FNM的准确性和较短的运行时间使其成为DLC系统设计、分析和优化的良好工具。服务器模块中的压降被发现占DLC机架中总压降的56%。进一步分析表明，服务器模块中69%的压降与模块的管道（波纹软管、断开器、接头）有关。服务器冷却模块旨在提供安全的连接和灵活性，这带来了高压降成本。
This study presents an experimental and numerical characterization of pressure drop in a commercially available direct liquid cooled (DLC) rack. It is important to investigate the pressure drop in the DLC system as it determines the required pumping power for the DLC system, which affects the energy efficiency of the data center. The main objective of this research is to assess the flow rate and pressure distributions in a DLC system to enhance the reliability and the cooling system efficiency. Other objectives of this research are to evaluate the accuracy of flow network modeling (FNM) in predicting the flow distribution in a DLC rack and identify manufacturing limitations in a commercial system that could impact the cooling system reliability. The main components of the investigated DLC system are: coolant distribution module (CDM), supply/return manifold module, and server module which contains a cold plate. Extensive experimental measurements were performed to study the flow distribution and to determine the pressure characteristic curves for the server modules and the coolant distribution module (CDM). Also, a methodology was described to develop an experimentally validated flow network model (FNM) of the DLC system to obtain high accuracy. The measurements revealed a flow maldistribution among the server modules, which is attributed to the manufacturing process of the micro-channel cold plate. The average errors in predicting the flow rate of the server module and the CDM using FNM are 2.5% and 3.8%, respectively. The accuracy and the short run time make FNM a good tool for design, analysis, and optimization for DLC systems. The pressure drop in the server module is found to account for 56% of the total pressure drop in the DLC rack. Further analysis showed that 69% of the pressure drop in the server module is associated with the module's plumbing (corrugated hoses, disconnects, fittings). The server cooling modules are designed to provide secured connections and flexibility, which come with a high pressure drop cost.