Compressible laminar flow in a capillary

Journal of Fluid Mechanics ◽

10.1017/s0022112093000011 ◽

1993 ◽

Vol 246 ◽

pp. 1-20 ◽

Cited By ~ 81

Author(s):

H. R. van den Berg ◽

C. A. ten Seldam ◽

P. S. van der Gulik

Keyword(s):

Equation Of State ◽

Laminar Flow ◽

Velocity Profile ◽

Mass Flow Rate ◽

Mass Flow ◽

Flow Rate

An equation based on the hydrodynamical equations of change is solved, analytically and numerically, for the calculation of the viscosity from the mass-flow rate of a steady, isothermal, compressible and laminar flow in a capillaiy. It is shown that by far the most dominant correction is that due to the compressibility of the fluid, computable from the equation of state. The combined correction for the acceleration of the fluid and the change of the velocity profile appears to be 1.5 times larger than the correction accepted to date.

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Effect of nanofluid properties and mass-flow rate on heat transfer of parabolic-trough concentrating solar system

Journal of Naval Architecture and Marine Engineering ◽

10.3329/jname.v16i1.30548 ◽

2019 ◽

Vol 16 (1) ◽

pp. 33-44 ◽

Cited By ~ 1

Author(s):

M.K. Islam ◽

Md. Hasanuzzaman ◽

N.A. Rahim ◽

A. Nahar

Keyword(s):

Heat Transfer ◽

Heat Transfer Coefficient ◽

Laminar Flow ◽

Turbulent Flow ◽

Transfer Coefficient ◽

Mass Flow Rate ◽

Mass Flow ◽

Flow Rate ◽

Parabolic Trough ◽

Concentrated Solar Energy

Sustainable power generation, energy security, and global warming are the big challenges to the world today. These issues may be addressed through the increased usage of renewable energy resources and concentrated solar energy can play a vital role in this regard. The performance of a parabolic-trough collector’s receiver is here investigated analytically and experimentally using water based and therminol-VP1based CuO, ZnO, Al2O3, TiO2, Cu, Al, and SiC nanofluids. The receiver size has been optimized by a simulation program written in MATLAB. Thus, numerical results have been validated by experimental outcomes under same conditions using the same nanofluids. Increased volumetric concentrations of nanoparticle is found to enhance heat transfer, with heat transfer coefficient the maximum in W-Cu and VP1-SiC, the minimum in W-TiO2 and VP1-ZnO at 0.8 kg/s flow rate. Changing the mass flow rate also affects heat transfer coefficient. It has been observed that heat transfer coefficient reaches its maximum of 23.30% with SiC-water and 23.51% with VP1-SiC when mass-flow rate is increased in laminar flow. Heat transfer enhancement drops during transitions of flow from laminar to turbulent. The maximum heat transfer enhancements of 9.49% and 10.14% were achieved with Cu-water and VP1-SiC nanofluids during turbulent flow. The heat transfer enhancements of nanofluids seem to remain constant when compared with base fluids during either laminar flow or turbulent flow.

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Evaluate the Cooling Performance of Transmit/Receive Module Cooling System in Active Electronically Scanned Array Radar

Electronics ◽

10.3390/electronics10091044 ◽

2021 ◽

Vol 10 (9) ◽

pp. 1044

Author(s):

Jun Su Park ◽

Dong-Jun Shin ◽

Sung-Hwan Yim ◽

Sang-Hyun Kim

Keyword(s):

Laminar Flow ◽

Mass Flow Rate ◽

Mass Flow ◽

Flow Rate ◽

Cooling System ◽

Cooling Performance ◽

Cooling Flow ◽

Fluid Analysis ◽

Design Requirements

The active electronically scanned array (AESA) radar consists of many transmit/receive (T/R) modules and is used to track missiles approaching destroyers and fighters. The performance of the AESA radar depends on the T/R module temperature. The T/R module temperature should be maintained under 80 °C to guarantee the performance of the AESA radar. In order to match the design requirements of the cooling system of the AESA radar, it is necessary to evaluate the cooling performance according to various operation/installation environments. In this study, computational fluid analysis was performed by changing the number of T/R modules and the coolant mass flow rate to evaluate the cooling performance of the AESA radar coolant channel. The number of T/R modules was changed from 2 to 16, and the number of coolant inlet Re was changed from 277 to 11,116. As a result, it was confirmed that the temperature increased as the number of T/R modules increased. In addition, when the coolant status was laminar flow, it was confirmed that the cooling performance was significantly lowered. Therefore, the coolant status should be transient or turbulence to decrease the temperature of the T/R module. Additionally, the correlation between the arrangement of the T/R module and the cooling flow must be considered to cool the AESA radar.

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Enthalpy Determination Methods for Compressor Performance Calculations

Volume 4: Turbo Expo 2007, Parts A and B ◽

10.1115/gt2007-27038 ◽

2007 ◽

Cited By ~ 3

Author(s):

David Ransom ◽

Klaus Brun ◽

Rainer Kurz

Keyword(s):

Equation Of State ◽

Mass Flow Rate ◽

Mass Flow ◽

Flow Rate ◽

Gas Mixture ◽

Performance Simulation ◽

Simple Process ◽

Compressor Performance ◽

Determination Methods ◽

Compressor Power

In the field of compressor performance simulation and measurement, the most commonly used method to evaluate compressor performance is based on the analysis of inlet and discharge pressures and temperatures. Combined with gas mixture properties and known mass flow rate, it is a simple process to determine overall compressor power and efficiency. However, the critical step in this process is the conversion of pressure, temperature, and gas property information into both actual and ideal enthalpy differences. In addition to the abundance of equation of state (EOS) formulations, there are also multiple methods commonly applied for the calculation of the enthalpy differences. This paper reviews several of the methods used for this critical calculation and provides a comparison using multiple gas compositions.

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