機櫃壓阻以及進風量均勻性對集裝箱式數據中心冷却性能影響的實驗研究

Experimental investigation regarding rack pressure resistance and inlet air volume uniformity on cooling performance of a container data center

王銳(Wang, Rui)

指導教授 ： 王啟川

國立交通大學/工學院/機械工程系所/碩士(2020年)

摘要

本文通過在集裝箱式數據中心中使用不同開孔率（F = 100%，58%和35.4%）的穿孔金屬板來實驗研究冷通道半封閉和全封閉情況下，機櫃壓阻分佈對機房整體冷卻性能的影響。後又引入熱線式風速量測網研究在冷通道全封閉情況下，固定穿孔金屬板開孔率（F=35.4%），機櫃進風量均勻性對機房整體冷卻性能的影響。機櫃入出口溫度分佈，RCI（機櫃冷卻指標）和SHI（供熱指數）以及機櫃出風口流量分佈用於評估半封閉和全封閉配置下的機櫃冷卻性能。
結果顯示：在冷通道半封閉情況下，機櫃頂部Part中會出現氣流逆轉現象，這在沒有佈置穿孔板的實驗組中表現尤為明顯。在下部三個Part中佈置穿孔板，可以部分抑制氣流逆轉，但不能完全消除。在頂部三個Part中佈置F = 35.4%的穿孔板，可以徹底消除氣流逆轉現象。但由於更強的側邊熱回流，機櫃A1的散熱性能會迅速下降。因此將冷通道全封閉，對於沒有佈置穿孔板的情況，冷通道全封閉下氣流逆轉現象更為嚴重。在機櫃所有Part中佈置F = 35.4%的穿孔板會使所有機櫃的RCI和SHI都會得到顯著改善，並且分別接近理想值100%和0，但其機櫃出風口溫度分佈由於受到機櫃運行中流量分佈的影響，並沒有達到完全均勻。無論是在冷通道半封閉還是全封閉情況下，佈置開孔率F = 35.4%的穿孔金屬板均有助於完全消除機櫃內部氣流逆流。
引入熱線式風速量測網後的實驗結果發現：冷通道全封閉時，單純降低系統總供風量能降低能耗但只會讓機櫃散熱性能變得更加糟糕，單純提升抽風風扇轉速會讓機櫃散熱性能變好，但提升能耗。若是能將兩者結合，降低總供風量的同時將機櫃頂部Part S1處的抽風風扇轉速提高，則能在減少空調系統能耗的同時，不會影響機櫃散熱性能並且有助於讓機櫃上下Part的風量分佈更加均勻，另外後續即使提升對應區域發熱量也依然不會降低機櫃散熱性能。均勻供風量對於機櫃進風量均勻性有一定影響，但不明顯。進一步改變機櫃抽風風扇轉速，使其每個Part抽風量從上到下遞減以及加裝導風板設計對提升機櫃進風量均勻性有顯著影響，其流量分佈變得幾乎完全均勻，機櫃出風面溫度分佈也因此得到改善，散熱性能達到最優。

關鍵字

集裝箱式數據中心 ； 壓阻分佈 ； 進風量均勻性 ； 冷通道封閉 ； 熱回流 ； 氣流逆轉

並列摘要

This paper uses perforated metal plates with different aperture ratios (F = 100%, 58%, and 35.4%) in a container data center to experimentally study the effect of the rack pressure resistance on the cooling performance of the data center in the case of semi-contained and fully contained configuration. Later, a hot-wire speed measurement net was used to study the effect of the cabinet’s inlet air volume uniformity on the cooling performance of a data center under semi-contained configuration with the fixed perforated metal plate aperture rate (F = 35.4%). Inlet and outlet temperature distribution, RCI (The Rack Cooling Index), SHI (Supply Heat Index) and cabinet outlet volume flow rate distribution are used to evaluate the cooling performance of the cabinet in semi-contained and fully contained configuration.
The results show that in the case of semi-contained configuration, the airflow reversal phenomenon will occur in the top part of the rack, which is particularly obvious in the case without perforated plates. Arranging perforated plates in the lower three parts can partially inhibit airflow reversal, but cannot completely eliminate it. Arranging F = 35.4% perforated plates in the top three parts can completely eliminate the phenomenon of airflow reversal. However, due to the stronger side heat recirculation, the heat dissipation performance of rack A1 will rapidly decrease. Therefore, fully contained configuration is used. For the case with no perforated plate, the phenomenon of reversed airflow is more serious. Arranging F = 35.4% perforated plates in all parts of the rack will significantly improve the RCI and SHI of all cabinets, and close to the ideal value of 100% and 0 respectively. However, the temperature distribution of the air outlet of the rack is not completely uniform due to the influence of the flow distribution during the operation of the data center. Regardless of whether the semi-contained or fully contained configuration, the arrangement of perforated metal plates with an aperture ratio of F = 35.4% can help completely eliminate the airflow reversal phenomenon inside the cabinet.
The results after using the hot-wire speed measurement net show that: when the cold aisle is fully closed, simply reducing the total air supply of the system can reduce energy consumption but only make the cooling performance of the cabinet worse. Simply increasing the speed of the fan will make the cooling performance better but increase energy consumption. If the two ways can be combined to reduce the total air supply and increase the speed of the fan at Part S1, it can reduce the energy consumption of the air conditioning system without affecting the cooling performance of the rack and help make the air volume distribution of the upper and lower parts of the rack more uniform. In addition, even if the heat generation in the corresponding area is increased, the cooling performance of the cabinet will not be reduced. The uniform air supply has a certain effect on the uniformity of the air intake to the cabinet, but it is not obvious. Further changing the speed of the cabinet exhaust fan, so that the airflow volume of each part decreases from top to bottom, and the installation of air deflectors has a significant impact on the uniformity of the air intake volume of the rack, its flow distribution becomes almost completely uniform, the outlet temperature distribution of the rack is improved, and the heat dissipation performance is optimized.

並列關鍵字

Container data center ； Pressure resistance distribution ； Inlet air volume uniformity ； Aisle containment ； Recirculation ； Airflow reversal

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