Heat Transfer for Supercritical Flow With TRACE

2021 ◽  
Author(s):  
Glenn Roth ◽  
J. W. Spore
Keyword(s):  
Heat Transfer ◽  
Supercritical Flow

Heat Transfer Enhancement by Flow Destabilization in Electronic Chip Configurations

1992 ◽  
Vol 114 (1) ◽  
pp. 35-40 ◽  
Author(s):  
C. H. Amon
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Enhancement ◽  
Large Scale ◽  
Wave Structure ◽  
Transfer Enhancement ◽  
Supercritical Flow ◽  
Flow Modulation ◽  
Nusselt Numbers ◽  
Passive Flow ◽  
Tollmien Schlichting

Numerical simulations of the flow pattern and forced convective heat transfer in geometries such as those encountered in cooling systems for electronic devices are presented. For Reynolds numbers above the critical one, Rc, these flows exhibit a traveling wave structure with laminar self-sustained oscillations at the least stable Tollmien-Schlichting mode frequency. Supercritical oscillatory flow induces large-scale convective patterns which lead to significant mixing and correspondingly heat transfer augmentation. Three techniques of heat transfer enhancement by flow destabilization are compared on an equal pumping basis: active flow modulation, passive flow modulation and supercritical flow destabilization. It is found that the best enhancement system regarding minimum power dissipation corresponds to passive flow modulation in the range of low Nusselt numbers. However, supercritical flow destabilization becomes competitive as the requirement for a higher Nusselt number begins to dominate the design choices.

The Basic Thermal Hydraulic Issues of Applying Supercritical Fluid to Nuclear Reactors

2017 ◽  
pp. 481-553
Author(s):  
Xiao Yan ◽  
Jinguang Zang ◽  
Ting Xiong ◽  
Xi Sui ◽  
Yanping Huang ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Supercritical Water ◽  
Nuclear Power ◽  
Flow Instability ◽  
Future Research ◽  
Validation Data ◽  
Supercritical Flow ◽  
Future Research Directions ◽  
Stability Issues ◽  
The Heat Transfer Coefficient

This chapter is mainly focused on illustrating some introductory progress on thermal hydraulic issues of supercritical water, including heat transfer characteristics, pressure loss characteristics, flow stability issues and numerical method. These works are mainly performed in Nuclear Power Institute of China (NPIC) these years, to give a basic idea of elementary but important topics in this area. An analytical method was proposed up to predict the heat transfer coefficient and friction coefficient based on the two-layer wall function. Flow instability experiments have been carried out in a two-parallel-channel system with supercritical water, aiming to provide an up-to-date knowledge of supercritical flow instability phenomena and initial validation data for numerical analysis. An in-house code has been developed in NPIC in order to better utilize and further expand the experimental results on supercritical flow instability. At last, some future research directions are suggested for reference.

scholarly journals Numerical Study on Influences of Drag Reducing Additive in Supercritical Flow of Kerosene in a Millichannel

Energies ◽  
2021 ◽  
Vol 14 (20) ◽  
pp. 6758
Author(s):  
Biao Li ◽  
Wenxi Li ◽  
Xin Zheng ◽  
Yue Wang ◽  
Mingming Tang ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Pressure Drop ◽  
Physical Properties ◽  
Numerical Study ◽  
Simulation Method ◽  
Inlet Temperature ◽  
Heat Transfer Characteristics ◽  
Supercritical Flow ◽  
Transfer Characteristics ◽  
Drag Reducing Additive

To improve the performance of a high-pressure refueling liquid oxy-kerosene engine, the influence of drag-reducing additive on the heat transfer characteristics in the supercritical flow of kerosene in a microchannel for regenerative cooling is explored. The finite-volume CFD numerical simulation method is applied using the RNG k-ε turbulence model and enhanced wall function. The current work faithfully represents the effect of the drag-reducing additive in kerosene through numerical calculations by combining a 10-component model for the physical properties of the kerosene and the Carreau non-Newtonian fluid constitutive model from rheological measurements. Results suggest that the 10-component kerosene surrogate can describe the supercritical physical properties of kerosene. The inlet temperature, inlet velocity, and the heat flux on the channel wall are driving factors for the supercritical kerosene flow and heat transfer characteristics. The pressure influence on the heat transfer is negligible. With polymer additives, the loss in pressure drop and heat transfer performance of supercritical kerosene flow decrease 46.8% and 37.5% respectively. The enhancement of engine thrust caused by reduction in pressure drop is an attractive improvement of concern.

Heat Transfer for Supercritical Flow With TRACE

2020 ◽  
Author(s):  
Jay Spore ◽  
Glenn Roth
Keyword(s):  
Heat Transfer ◽  
Experimental Data ◽  
Critical Temperature ◽  
Single Phase ◽  
Supercritical Pressure ◽  
Significant Error ◽  
Heat Transfer Correlation ◽  
Supercritical Flow ◽  
Fluid Properties ◽  
Supercritical Flows

Abstract Flow regimes at water pressures above the critical pressure are characterized as supercritical flow. Supercritical flows have no phase change. The heat transfer from the wall to the fluid is single phase (there is no boiling or condensation). Experimental data indicate that for conditions that involve supercritical single-phase heat transfer, the Dittus-Boelter heat transfer correlation can be in significant error. A pseudo-critical temperature can be defined as a function of pressure for pressures that exceed the supercritical pressure. The pseudo-critical temperature is defined for heat transfer purposes as the temperature at which the specific heat peaks as the pressure is held constant. There is significant variation in fluid properties across the heat transfer boundary layer at temperatures near the pseudo-critical temperature. The large variation in properties is the reason for the failure of the Dittus-Boelter heat transfer correlation. Comparisons to experimental data indicate that the Mokry heat transfer correlation is a significant improvement over the Dittus-Boelter heat transfer correlation for single phase supercritical heat transfer. The Mokry correlation was chosen to be included into TRACE.

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