Flow and Heat Transfer Experimental Investigation and Numerical Simulation of Single-Phase Liquid Nitrogen in Micro-Tube at Low Temperature and High Pressure

2018 ◽  
Vol 13 (6) ◽  
pp. 886-896
Author(s):  
Kai-Xuan Liu ◽  
Chun-An Ai ◽  
Bei Chen Zhang ◽  
Xue-Ren Wang ◽  
Jian Li ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Numerical Simulation ◽  
Experimental Investigation ◽  
High Pressure ◽  
Low Temperature ◽  
Liquid Nitrogen ◽  
Single Phase ◽  
Flow And Heat Transfer ◽  
Phase Liquid

A Review of Single-Phase Liquid Flow and Heat Transfer in Microchannels

2004 ◽  
Author(s):  
Peiqing Shen ◽  
Shahrouz K. Aliabadi ◽  
Jalal Abedi
Keyword(s):  
Heat Transfer ◽  
Fluid Flow ◽  
Single Phase ◽  
Research Area ◽  
Theoretical Explanation ◽  
Conventional Theory ◽  
Flow And Heat Transfer ◽  
Important Research Area ◽  
Phase Liquid ◽  
Liquid Flows

Fluid flow and heat transfer in microchannels have been important research area during the past decade. The understanding and explanation of the fundamental mechanisms of flow and heat transfer are critical to the application of microchannel systems to many important industrial and research projects. We present a review of the literatures on fluid flow and heat transfer of single-phase liquid in microchannels. Recent experimental and theoretical studies are both covered. The emphasis has been on studies on single-phase liquid flows. As a conclusion, although further work needs to be done, carefully designed experiments have obtained data that agree well with the conventional theory developed for larger channels. The theoretical explanation of some experimental results, which deviate the conventional theory for larger channels, is still under development.

scholarly journals Numerical Simulation and Design of a High-Temperature, High-Pressure Fluid Transport Pipe

2020 ◽  
Vol 10 (17) ◽  
pp. 5890
Author(s):  
Jiyoung Yoon ◽  
Junkyu Park ◽  
Jinhyoung Park
Keyword(s):  
Heat Transfer ◽  
Numerical Simulation ◽  
High Pressure ◽  
High Temperature ◽  
Low Temperature ◽  
Fluid Transport ◽  
Projectile Velocity ◽  
Gas Leakage ◽  
And Performance ◽  
High Temperature High Pressure

When designing a hand caliber with a high-temperature, high-pressure internal fluid transport pipe, reliability, safe use, and performance must be considered. Reliability refers to the stress caused by thermo-mechanical load; safe use refers to the low-temperature burns that might occur upon contact, and high-temperature burns caused by gas leakage occurring in the cylinder gap; and performance refers to projectile velocity. In this study, numerical simulation methods for heat transfer, structure analysis, and gas leakage are proposed so that solutions can be designed to account for the above three criteria. Furthermore, a hand-caliber design guide is presented. For heat transfer and structural analysis, mesh size, the transient convective heat transfer coefficient, and boundary conditions are described. Regarding gas leakage, methods reflecting projectile motion and determination of the molecular weight of the propellant are described. As a result, a designed hand caliber will have a high reliability, because the thermo-mechanical stress is lower than the yield stress. There will be little risk of low-temperature burns, but there will be a high temperature-burn risk, owing to gas leakage in the cylinder gap. The larger the cylinder-gap size, the greater the gas leakage and the smaller projectile velocity. The presented numerical simulation method can be applied to evaluate various aspects of other structures that require high-temperature, high-pressure fluid-transport pipes.

scholarly journals Effects of Temperature on the Flow and Heat Transfer in Gel Fuels: A Numerical Study

Energies ◽  
2020 ◽  
Vol 13 (4) ◽  
pp. 821
Author(s):  
Qin-Liu Cao ◽  
Wei-Tao Wu ◽  
Wen-He Liao ◽  
Feng Feng ◽  
Mehrdad Massoudi
Keyword(s):  
Heat Transfer ◽  
Low Temperature ◽  
Transport System ◽  
Apparent Viscosity ◽  
Thermal Design ◽  
Straight Pipe ◽  
Heating Wall ◽  
Supply Pressure ◽  
Flow And Heat Transfer ◽  
The Mean

In general, rheological properties of gelled fuels change dramatically when temperature changes. In this work, we investigate flow and heat transfer of water-gel in a straight pipe and a tapered injector for non-isothermal conditions, which mimic the situations when gelled fuels are used in propulsion systems. The gel-fluid is modeled as a non-Newtonian fluid, where the viscosity depends on the shear rate and the temperature; a correlation fitted with experimental data is used. For the fully developed flow in a straight pipe with heating, the mean apparent viscosity at the cross section when the temperature is high is only 44% of the case with low temperature; this indicates that it is feasible to control the viscosity of gel fuel by proper thermal design of pipes. For the flow in the typical tapered injector, larger temperature gradients along the radial direction results in a more obvious plug flow; that is, when the fuel is heated the viscosity near the wall is significantly reduced, but the effect is not obvious in the area far away from the wall. Therefore, for the case of the tapered injector, as the temperature of the heating wall increases, the mean apparent viscosity at the outlet decreases first and increases then due to the high viscosity plug formed near the channel center, which encourages further proper design of the injector in future. Furthermore, the layer of low viscosity near the walls plays a role similar to lubrication, thus the supply pressure of the transport system is significantly reduced; the pressure drop for high temperature is only 62% of that of low temperature. It should be noticed that for a propellent system the heating source is almost free; therefore, by introducing a proper thermal design of the transport system, the viscosity of the gelled fuel can be greatly reduced, thus reducing the power input to the supply pressure at a lower cost.

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