Cluster of High Powered Racks Within a Raised Floor Computer Data Center: Effect of Perforated Tile Flow Distribution on Rack Inlet Air Temperatures

Author(s):  
Roger Schmidt ◽  
Ethan Cruz

This paper focuses on the effect on inlet rack air temperatures as a result of maldistribution of airflows exiting the perforated tiles located adjacent to the fronts of the racks. The flow distribution exiting the perforated tiles was generated from a computational fluid dynamics (CFD) tool called Tileflow (Trademark of Innovative Research, Inc.). Both raised floor heights and perforated tile free area were varied in order to explore the effect on rack inlet temperatures. The flow distribution exiting the perforated tiles was used as boundary conditions to the above floor CFD model. A CFD model was generated for the room with electronic equipment installed on a raised floor. Fourty racks of data processing (DP) equipment were arranged in rows in a data center cooled by chilled air exhausting from perforated floor tiles. The chilled air was provided by four A/C units placed inside a room 12.1 m wide × 13.4 m long. Since the arrangement of the racks in the data center was symmetric only one-half of the data center was modeled. The numerical modeling for above the raised floor was performed using a commercially available finite control volume computer code called Flotherm (Trademark of Flomerics, Inc.). The flow was modeled using the k-e turbulence model. Results are displayed to provide some guidance on the design and layout of a data center.

2004 ◽  
Vol 126 (4) ◽  
pp. 510-518 ◽  
Author(s):  
Roger Schmidt ◽  
Ethan Cruz

This paper focuses on the effect on rack inlet air temperatures as a result of maldistribution of airflows exiting the perforated tiles located adjacent to the fronts of the racks. The flow distribution exiting the perforated tiles was generated from a computational fluid dynamics (CFD) tool called Tileflow (trademark of Innovative Research, Inc.). Both raised floor heights and perforated tile-free areas were varied in order to explore the effect on rack inlet temperatures. The flow distribution exiting the perforated tiles was used as boundary conditions to the above-floor CFD model. A CFD model was generated for the room with electronic equipment installed on a raised floor. Forty racks of data processing (DP) equipment were arranged in rows in a data center cooled by chilled air exhausting from perforated floor tiles. The chilled air was provided by four A/C units placed inside a room 12.1 m wide×13.4 m long. Because the arrangement of the racks in the data center was symmetric, only half of the data center was modeled. The numerical modeling for the area above the raised floor was performed using a commercially available finite control volume computer code called Flotherm (trademark of Flomerics, Inc.). The flow was modeled using the k-e turbulence model. Results are displayed to provide some guidance on the design and layout of a data center.


Author(s):  
Roger Schmidt ◽  
Ethan Cruz

This paper focuses on the effect on inlet rack air temperatures when adjacent racks are removed. Only the above floor (raised floor) flow and temperature distributions were analyzed for various air flowrates exhausting from the perforated tiles and the rack. A Computational Fluid Dynamic (CFD) model was generated for the room with electronic equipment installed on a raised floor with particular focus on the effects on rack inlet temperatures of these high powered racks. The baseline case was with forty racks of data processing (DP) equipment arranged in rows in a data center cooled by chilled air exhausting from perforated floor tiles. The chilled air was provided by four A/C units placed inside a room 12.1 m wide × 13.4 m long. Since the arrangement of the racks in the data center was symmetric only one-half of the data center was modeled. To see the effect of missing racks adjacent to high powered racks various configurations were analyzed. The numerical modeling was performed using a commercially available finite control volume computer code called Flotherm (Trademark of Flomerics, Inc.). The flow was modeled using the k-e turbulence model. Results are displayed to provide some guidance on the design and layout of a data center.


Author(s):  
Roger Schmidt ◽  
Ethan Cruz

This paper focuses on the effect on inlet rack air temperatures when rack flowrates are reduced. Reduced flowrates for the same heat loads results in higher air temperature differences across the rack and thereby higher air temperatures exiting the rack. The effect of the higher rack exhaust temperatures on the inlet rack air temperatures is the focus of this investigation. Only the above floor (raised floor) flow and temperature distributions were analyzed for a range of rack flowrates and with various flowrates exhausting from the perforated tiles. A Computational Fluid Dynamic (CFD) model was generated for the room with electronic equipment installed on a raised floor with particular focus on the effects on rack inlet temperatures of these high powered racks. Fourty racks of data processing (DP) equipment were arranged in rows in a data center cooled by chilled air exhausting from perforated floor tiles. The chilled air was provided by four A/C units placed inside a room 12.1 m wide × 13.4 m long. Since the arrangement of the racks in the data center was symmetric only one-half of the data center was modeled. The numerical modeling was performed using a commercially available finite control volume computer code called Flotherm (Trademark of Flomerics, Inc.). The flow was modeled using the k-e turbulence model. Results are displayed to provide some guidance on the design and layout of a data center.


Author(s):  
Roger Schmidt ◽  
Ethan Cruz

This paper focuses on the effect on inlet rack air temperatures when high-powered racks are situated amongst lower powered racks in a raised floor data center. Only the above floor (raised floor) flow and temperature distributions were analyzed for various flowrates exhausting from the perforated tiles and with one or two high powered racks placed at various locations amongst the lower powered racks. A Computational Fluid Dynamic (CFD) model was generated for the room with electronic equipment installed on a raised floor with particular focus on the effects on rack inlet temperatures of these high powered racks. Forty racks of data processing (DP) equipment were arranged in rows in a data center cooled by chilled air exhausting from perforated floor tiles. The chilled air was provided by four A/C units placed inside a room 12.1 m wide × 13.4 m long. Since the arrangement of the racks in the data center was symmetric only one-half of the data center was modeled. The numerical modeling was performed using a commercially available finite control volume computer code called Flotherm (Trademark of Flomerics, Inc.). The flow was modeled using the k-e turbulence model. Results are displayed to provide some guidance on the design and layout of a data center.


Author(s):  
Pramod Kumar ◽  
Vikneshan Sundaralingam ◽  
Yogendra Joshi ◽  
Michael K. Patterson ◽  
Robin Steinbrecher ◽  
...  

In this paper we experimentally investigate the effect of supply air temperature on rack cooling in a high density raised floor data center facility. A series of experiments are performed on a 42 U (1-U = 4.45 cm) rack populated with 1-U servers. Desired rack heat loads are achieved by managing the distribution of server compute load within the rack. During the present experiments, temperatures at various locations in the hot and cold aisle corresponding to the rack air inlet and outlet are recorded. The temperatures are measured using a grid consisting of 256 thermocouples. The temperature measurements are further complimented with the flow field at the rack inlet. Particle Image Velocimetry (PIV) technique is used to capture the flow field at the rack inlet. The temperature maps in concert with the PIV flow field help in quantifying the rack cooling effectiveness. The temperature and flow measurements are measured for various cases by altering the supply air temperatures and perforated tile flow rates. The results are analyzed and compared with the ASHRARE recommended guidelines to arrive at the optimum supply air temperature. A perceptible change in the temperature and flow distribution is observed for the six cases investigated.


1994 ◽  
Vol 116 (2) ◽  
pp. 134-137 ◽  
Author(s):  
Ronald L. Linton ◽  
D. Agonafer

This paper presents an alternative approach to modeling box cooling in electronic packages. A finite-control-volume simulation code is used to simulate an IBM desktop Personal Computer. Only the geometry, the overall air flow rate, the turbulent viscosity and the power dissipations from each card must be specified. The simulation code predicts the flow distribution inside the PC, the convection coefficients, the turbulence effects, and the temperatures. Predicted component temperatures were compared to measured values.


Author(s):  
Shrishail Guggari ◽  
Dereje Agonafer ◽  
Christian Belady ◽  
Lennart Stahl

Today’s data centers are designed for handling heat densities of 1000W/m2 at the room level. Trends indicate that these heat densities will exceed 3000W/m2 in the near future. As a result, cooling of data centers has emerged as an area of increasing importance in electronics thermal management. With these high heat loads, data center layout and design cannot rely on intuitive design of air distribution and requires analytical tools to provide the necessary insight to the problem. These tools can also be used to optimize the layout of the room to improve energy efficiency in the data center. In this paper, first an under floor analysis is done to find an optimized layout based on flow distribution through perforated tiles, then a complete Computational Fluid Dynamics (CFD) model of the data center facility is done to check for desired cooling and air flow distribution throughout the room. A robust methodology is proposed which helps for fast, easy, efficient modeling and analysis of data center design. Results are displayed to provide some guidance on the layout and design of data center. The resulting design approach is very simple and well suited for the energy efficient design of complex data centers and server farms.


Author(s):  
Zachary M. Pardey ◽  
James W. VanGilder ◽  
Christopher M. Healey ◽  
David W. Plamondon

Calibrating a CFD model against measured data is the first step to successfully utilizing this technology for change-management and the optimization of an existing data center. To date, there has been very little published on this calibration process; more focus has been placed on the use of CFD at the design stage and the development of modeling techniques and solvers. Further, few studies which feature comprehensive comparisons of CFD-predicted and measured data have been published for real data centers, and many that have, demonstrated only modest agreement at best. This study provides another such comparison — for a 7,400 ft2 (687 m2), 138-rack, raised-floor facility. The goals of the study are to benchmark the level of agreement that can be practically obtained and also to investigate the level of modeling detail required. Additionally, specific practical advice covering both CFD modeling and experimental measurements is provided. A plenum-only CFD model is compared to measured tile airflow rates and a room-model, which uses measured tile flow rates as boundary conditions, is compared to temperatures measured at each rack inlet. The level of agreement is among the best published to date and demonstrates that a CFD model can be adequately calibrated against measured data and is of value for ongoing data center operation.


2018 ◽  
Vol 14 (03) ◽  
pp. 142
Author(s):  
Jinsuo Lu ◽  
Wei Zhang ◽  
Dengyu Wang ◽  
Xiaoyi Wang

<p class="16">Water intake with fixed height limits the application of selective withdrawal technology in a certain degree. This study proposes a technological idea to install baffles on water intake. Through the rotation of upper and lower baffle, poor water layer can be blocked. A Computational Fluid Dynamics (CFD) model for the upper baffle on water intake is constructed. The results show that the baffle installed on the upper part of orifice can reduce the withdrawal layer thickness and flow on the upper part of orifice centre. Thereby, the withdrawal flow on lower part can be indirectly increased. While, baffle length and inclining angle are the important factors to influence the withdrawal layer thickness and flow distribution. Therefore, the adjusting range of selective withdrawal can be economically enhanced by installing baffles on water intake.</p>


Author(s):  
Zheji Liu ◽  
D. Lee Hill ◽  
Gary Colby

A radial sidestream inlet is commonly utilized in multi-stage centrifugal compressors to introduce additional gas into the mid-stage of the compressor. The flow distribution after the junction of the sidestream and the main return channel of the upstream stage can significantly affect the performance of the next stage. In this study, the mixing between the fluid from the sidestream component and the fluid from the main return channel was investigated numerically using Computational Fluid Dynamics (CFD). A variety of CFD models of different geometry, different boundary conditions, and different grid density were developed to analyze the uniformity of the flow entering the impeller of the next stage. The flow distribution difference between the sidestream CFD model and the CFD model with the sidestream coupled to the main return channel suggests that both the return channel and the sidestream have to be modeled together to get meaningful results. The results of this effort were used in conjunction with production test data to help resolve a performance shortfall of a multi-stage centrifugal compressor with sidestream injection. The test data from the final design is also provided to show the resulting improvement in head rise.


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