0311 Study on Internal Flow of High Pressure-High Flow Rate Small-sized Cooling Fan

It is important in development of turbomachinery to predict their performance precisely. Especially the prediction of multistage pump performance is one of the challenging problems because internal phenomena which relate to the performance are complicated. Therefore, in this research, we verified accuracy of Computational Fluid Dynamics (CFD) in predicting performance of a five-stage high-pressure volute pump by comparing predicted values by CFD with measurement data. We tried two methods to predict the pump performance. One is a computation with a complete pump model which includes all five stages and leakage passages. This method can be expected to represent total internal flow phenomena. The other method is totaling up the performance data from separate computations of 1st–2nd stages and series stages. This method is simpler than the former and involves less computational cost. As a result, it was clarified that all the methods could predict pump head at the best efficiency point to some extent, even by steady computation. However, no prediction can predict positive gradient in Q-H curve which was observed in measurement at low flow rate. Except for the unsteady complete pump model computation, efficiency and shaft power could not be predicted precisely. In addition, at high flow rate, unsteady computation of the complete pump model shows the best agreement in head. In the complete pump model computation at high flow rate, the series stage next to the long crossover has larger head because of the influence of it. Therefore, the separated model has difficulty in representing series stages’ performance. In order to predict performance at high flow rate, unsteady computations also including properly the influence of the long crossover properly are necessary. In addition, to predict performance at low flow rate, unsteady computation is necessary.

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Performance Characteristics and Flow Conditions of High Pressure and Large Flow Rate Cooling Fan

Volume 1B, Symposia: Fluid Machinery; Fluid Power; Fluid-Structure Interaction and Flow-Induced Noise in Industrial Applications; Flow Applications in Aerospace; Flow Manipulation and Active Control: Theory, Experiments and Implementation; Fundamental Issues and Perspectives in Fluid Mechanics ◽

10.1115/fedsm2013-16273 ◽

2013 ◽

Author(s):

Toru Shigemitsu ◽

Junichiro Fukutomi ◽

Takuya Agawa

Keyword(s):

High Pressure ◽

Flow Rate ◽

Data Center ◽

Flow Condition ◽

Internal Flow ◽

Design Guideline ◽

Cooling Fan ◽

Large Flow Rate ◽

Cooling Fans ◽

Large Flow

Data center has been built with spread of cloud computing. Further, electric power consumption of it is growing rapidly. High pressure and large flow rates small-sized cooling fans are used for servers in the data center and there is a strong demand to increase pressure and flow rate of it because of increase of quantity of heat from the servers. Contra-rotating rotors have been adopted for some of the high pressure and large flow rate cooling fans to meet the demand of it. There is limitation of space for servers and geometrical restriction for cooling fan because spokes to support the fan motor, electrical power cables and so on should be installed in the cooling fan. It is important to clarify performance of each front and rear rotor of contra-rotating small-sized cooling fan and internal flow condition to achieve the high performance cooling fans. In the present paper, detailed performance and the flow condition around the rotor of the high pressure and large flow rate contra-rotating small-sized axial fan with 40mm square casing are investigated. Pressure, shaft power and efficiency curves of each front and rear rotor are clarified by the experimental and the numerical results. Furthermore, the internal flow condition of the rear rotor is clarified by the numerical analysis results and design guideline to improve the performance is discussed by these results.

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A Piezoelectrically-Actuated Valve for Modulation of Liquid at High Flow Rate Under High Pressure

TRANSDUCERS 2007 - 2007 International Solid-State Sensors, Actuators and Microsystems Conference ◽

10.1109/sensor.2007.4300237 ◽

2007 ◽

Cited By ~ 1

Author(s):

Srihari Rajgopal ◽

Aaron Knobloch ◽

Stacey Kennerly ◽

Mehran Mehregany

Keyword(s):

High Pressure ◽

Flow Rate ◽

High Flow ◽

High Flow Rate

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Development of a novel parallel-spool pilot operated high-pressure solenoid valve with high flow rate and high speed

Chinese Journal of Mechanical Engineering ◽

10.3901/cjme.2015.0104.001 ◽

2015 ◽

Vol 28 (2) ◽

pp. 369-378 ◽

Cited By ~ 2

Author(s):

Dai Dong ◽

Xiaoning Li

Keyword(s):

High Pressure ◽

Flow Rate ◽

High Speed ◽

Solenoid Valve ◽

High Flow ◽

High Flow Rate

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Experimental Investigation of Relationship Between Pressure Fluctuations and Vibrations for a Double Suction Centrifugal Pump

ASME-JSME-KSME 2011 Joint Fluids Engineering Conference: Volume 1, Symposia – Parts A, B, C, and D ◽

10.1115/ajk2011-06014 ◽

2011 ◽

Author(s):

Zhifeng Yao ◽

Fujun Wang ◽

Ruofu Xiao ◽

Chenglian He ◽

Zhuqing Liu

Keyword(s):

Flow Rate ◽

Large Scale ◽

Pressure Fluctuations ◽

Primary Source ◽

Internal Flow ◽

Rotational Frequency ◽

High Flow ◽

High Flow Rate ◽

Centrifugal Pumps ◽

Blade Passing Frequency

Double-suction centrifugal pumps are widely employed in large-scale pumping stations, which generally run in the conditions of large discharge with huge energy consumption. Pressure fluctuation caused by internal flow due to tongue-impeller interaction is the primary source of pump vibration. In this paper, pressure fluctuations and vibrations signals on volute casing wall were experimentally obtained at five flow rates ranging from 59% to 121% of nominal flow rate. Time and frequency domains of the signals were mainly analyzed by using statistical and fast Fourier transform methods. The results show that rotational frequency, blade passing frequency and their harmonic frequencies of pressure fluctuations as well as vibrations are clearly identified. The magnitude at blade passing frequency has close relationship with the measurement location related to the volute tongue, and becomes larger when the flow rate deviates from the nominal flow rate. The magnitudes at blade passing frequency can increase by 70% and 151% at high flow rate over that at the nominal flow rate for pressure fluctuations and vibrations, respectively. While the magnitude of vibration at rotational frequency keeps nearly constant at partial flow rate, and decreases at high flow rate.

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High-Pressure, High-Flow-Rate Stimulation Equipment for Shale Fracture Treatments

10.2118/194880-ms ◽

2019 ◽

Author(s):

Jim B. Surjaatmadja ◽

Tom Logan ◽

Timothy H. Hunter ◽

Stanley V. Stephenson ◽

Brad Bull ◽

...

Keyword(s):

High Pressure ◽

Flow Rate ◽

High Flow ◽

High Flow Rate ◽

Shale Fracture

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Design of the Cascaded Open-Channel Direct Current Electroosmotic Pump

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.483.259 ◽

2011 ◽

Vol 483 ◽

pp. 259-263 ◽

Cited By ~ 1

Author(s):

Ting Ting Liu ◽

Zhu Chuan Bai ◽

Yang Gao

Keyword(s):

High Pressure ◽

Flow Rate ◽

Direct Current ◽

Open Channel ◽

Cooling System ◽

Test System ◽

High Flow ◽

High Flow Rate ◽

Driving Voltage ◽

Electroosmotic Pump

Electroosmotic pump does not need moving mechanical parts, which can be fabricated by micromachining process and integrated with other micro-devices. Electroosmotic pump is the hydraulic actuator component and can be used in HPLC (High Pressure Liquid Chromatography), μTAS (Micro totally analysis system), chip test system, micro cooling system and micro drug delivery system, etc. The paper is to design an electroosmotic pump with low driving voltage, high pressure and high flow rate, and fabricate the samples of cascaded open-channel direct current electroosmotic pump. The three-dimensional model of one-stage parallel open-channel electroosmotic pump is established by finite element analysis software of CoventorWare. The numerical simulation of the electroosmotic pump performance has been done by CoventorWare. Compared with the equivalent circuit model, the results show that the cascaded open-channel direct current electroosmotic pump has the advantages of high flow rate and high pressure.

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Optimization of the Orifice Shape of Cooling Fan Units for High Flow Rate and Low-Level Noise in Outdoor Air Conditioning Units

Applied Sciences ◽

10.3390/app9235207 ◽

2019 ◽

Vol 9 (23) ◽

pp. 5207 ◽

Cited By ~ 3

Author(s):

Se Min Park ◽

Seo-Yoon Ryu ◽

Cheolung Cheong ◽

Jong Wook Kim ◽

Byung Il Park ◽

...

Keyword(s):

Noise Reduction ◽

Flow Rate ◽

Stokes Equations ◽

Low Noise ◽

High Flow ◽

High Flow Rate ◽

Air Conditioner ◽

Air Conditioners ◽

Flow Noise ◽

Cooling Fan

Demand for air conditioners is steadily increasing due to global warming and improved living standards. The noise, as well as the performance of air conditioners, are recognized as one of the crucial factors that determine the air conditioners’ values. The performance and noise of the air conditioner are mostly determined by those of its outdoor unit, which in turn depend on those of the cooling fan unit. Therefore, a cooling fan unit of high-performance and low noise is essential for air-conditioner manufacturers and developers. In this paper, the flow performance and flow noise of the entire outdoor unit with an axial cooling fan in a split-type air-conditioner were investigated. First, a virtual fan tester constructed by using about 18 million grids is developed for highly resolved flow simulation. The unsteady Reynolds-Averaged Navier–Stokes equations are numerically solved by using finite-volume computational fluid dynamics techniques. To verify the validity of the numerical analysis, the predicted P–Q curve of the cooling fan in a full outdoor unit is compared with the measured one. There was an excellent agreement between the two curves. The further detailed analysis identifies the coherent vortex structures between the fan blade tip and fan orifice, which adversely affect the flow performance and causes flow noise. Based on this analysis, the optimization of fan orifice was carried out using the response surface method with three geometric parameters: inlet radius, neck length, and outlet angel of the orifice. The optimum layout for the high flow rate is proposed under the understanding that the increased flow rate can be converted to noise reduction. The additional computation using the proposed optimum orifice shows that the flow rate is increased by 4.6% at the operating point. Finally, the engineering sample was manufactured by using the optimum design, and the measured data confirmed that the flow rate were increased by 2.1%, the noise reduction was made by 2.8 dBA, and the power consumption is reduced by 4.0% at the operating rotational speed.

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