Investigating the effect of submerged impingement jet on heat transfer in water-alcohol mixtures

Abstract This paper presents new results of experiments on spherical sample cooling with submerged impingement jet in subcooled water-alcohol mixtures. The influence of the ethanol concentration on the occurrence of intensive boiling regime is detected. Experiments are carried out on a stainless-steel sample in a water-ethanol mixture, in a wide range of concentrations and temperatures. The result includes an increase of the heat transfer intensity at exposure of the submerged impingement jet. The intensive boiling regime is detected with a higher ethanol content compared to experiments in a calm liquid.

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Equation of state for water-alcohol mixtures over a wide range of state variables

Russian Journal of Physical Chemistry A ◽

10.1134/s0036024415090150 ◽

2015 ◽

Vol 89 (9) ◽

pp. 1545-1555 ◽

Cited By ~ 1

Author(s):

B. K. Karabekova ◽

E. A. Bazaev

Keyword(s):

Equation Of State ◽

State Variables ◽

Wide Range ◽

Alcohol Mixtures ◽

Water Alcohol

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Theoretical and Numerical Analysis of Freezing Risk During LNG Evaporation Process

Energies ◽

10.3390/en12081426 ◽

2019 ◽

Vol 12 (8) ◽

pp. 1426 ◽

Cited By ~ 6

Author(s):

Zbigniew Rogala ◽

Arkadiusz Brenk ◽

Ziemowit Malecha

Keyword(s):

Heat Transfer ◽

Phase Formation ◽

Solid Phase ◽

Significant Risk ◽

Equilibrium Temperature ◽

Large Temperature ◽

Boiling Regime ◽

Wide Range ◽

Theoretical And Numerical Analysis ◽

Liquid Natural Gas

The liquid natural gas (LNG) boiling process concerns most LNG applications due to a need for regasification. Depending on the pressure, the equilibrium temperature of LNG is 112–160 K. The low boiling temperature of LNG makes the vaporization process challenging because of a large temperature difference between the heating medium and LNG. A significant risk included in the regasification process is related to the possibility of solid phase formation (freezing of the heating fluid). A solid phase formation can lead to an increase in pressure loss, deterioration in heat transfer, or even to the destruction of the heat exchanger. This prompts the need for a better understanding of the heat transfer during the regasification process to help avoid a solid phase formation. The present research is focused on the investigation of the mutual interactions between several parameters, which play a significant role in the regasification process. The research is based on a zero-dimensional (0D) model, which was validated through the comparison with a state-of-the-art Computational Fluid Dynamics (CFD) model. This made fast calculations and the study of the risk of freezing for a wide range of parameter space possible, including the LNG boiling regime. The boiling regime of LNG was shown to be a key factor in determining the risk of freezing.

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Effect of Agitation, Temperature, and Quenching Medium on Cooling Curve and cooling rate for Steels

Al-Nahrain Journal for Engineering Sciences ◽

10.29194/njes.21040473 ◽

2018 ◽

Vol 21 (4) ◽

pp. 473-478

Author(s):

Hala S. Hasan ◽

Reham H. Khaleefah ◽

Nasser A. Al haboubi ◽

Raad D. Salman

Keyword(s):

Heat Transfer ◽

Steel Sample ◽

Cooling Curve ◽

Temperature History ◽

Stainless Steel Sample ◽

Cooling Curves ◽

Ability To Work ◽

Cooling Stage ◽

Quenching Process ◽

Transfer Properties

The control of quenching process has been investigated in this study by developing a quench system design to simulate the quenching process and measure the time – temperature history inside the sample during the cooling stage. The main purpose of this quench system is to evaluate the quench power of different quenchant at different conditions (type, temperature and agitation).A stainless steel sample was used with a suitable measurement as a probe in designing this quench system.The performance of two of quenchants (water and brine) with different conditions was investigated, and the designed probe was used to illustrate the effect of quenching parameters (quenchant type, temperature and its agitation) on cooling curves and cooling rate.The quenching system has proven its ability to work effectively and the results showed that heat transfer properties were significantly affected by quenchant parameters.

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An Experimental Study of Heat Pipe Performance Using Binary Mixture Fluids That Exhibit Strong Concentration Marangoni Effects

Journal of Thermal Science and Engineering Applications ◽

10.1115/1.4004399 ◽

2011 ◽

Vol 3 (3) ◽

Cited By ~ 13

Author(s):

Kenneth M. Armijo ◽

Van P. Carey

Keyword(s):

Heat Transfer ◽

Heat Flux ◽

Heat Transfer Coefficient ◽

Heat Pipe ◽

Pure Water ◽

Working Fluid ◽

Strong Concentration ◽

Alcohol Mixtures ◽

Marangoni Effects ◽

Water Alcohol

This paper summarizes the results of an experimental investigation of the performance characteristics of a gravity/capillary driven heat pipe using water/alcohol mixtures as a working fluid. This investigation specifically explored the use of water/alcohol mixtures that exhibit strong concentration-based Marangoni effects. Experiments to determine heat pipe performance were conducted for pure water and water/alcohol solutions with increasing concentrations of alcohol. Initial tests with pure water determined the optimal working fluid charge for the heat pipe; subsequent performance tests over a wide range of heat input levels were then conducted for each working fluid at this optimum value. The results indicate that some mixtures can significantly enhance the heat transfer coefficient and heat flux capability of the heat pipe evaporator. For the best mixture tested, the maximum evaporator heat flux carried by the coolant without dryout was found to be 52% higher than the value for the same heat pipe using pure water as a coolant under comparable conditions. Peak evaporator heat flux values above 100 W/cm2 were achieved with some mixtures. Evaporator and condenser heat transfer coefficient data are presented, and the trends are examined in the context of the expected effect of the Marangoni mechanisms on heat transfer.

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An Experimental Study of Heat Pipe Performance Using Binary Mixture Fluids That Exhibit Strong Concentration Marangoni Effects

2010 14th International Heat Transfer Conference, Volume 5 ◽

10.1115/ihtc14-23255 ◽

2010 ◽

Cited By ~ 2

Author(s):

Kenneth M. Armijo ◽

Van P. Carey

Keyword(s):

Heat Transfer ◽

Heat Flux ◽

Heat Transfer Coefficient ◽

Heat Pipe ◽

Pure Water ◽

Working Fluid ◽

Strong Concentration ◽

Alcohol Mixtures ◽

Marangoni Effects ◽

Water Alcohol

This paper summarizes the results of an experimental investigation of the performance characteristics of a gravity/capillary driven heat pipe using water/alcohol mixtures as a working fluid. This investigation specifically explored the use of water/alcohol mixtures that exhibit strong concentration-based Marangoni effects. Experiments to determine heat pipe performance were conducted for pure water and water/alcohol solutions with increasing concentrations of alcohol. Initial tests with pure water determined the optimal working fluid charge for the heat pipe; subsequent performance tests over a wide range of heat input rates were then conducted for each working fluid at this optimum value. The results indicate that some mixtures can significantly enhance the heat transfer coefficient and heat flux capability of the heat pipe evaporator. For the best mixture tested, the maximum evaporator heat flux carried by the coolant without dryout was found to be 52% higher than the value for the same heat pipe using pure water as a coolant under comparable conditions. Peak evaporator heat fluxes above 100 W/cm2 were achieved with some mixtures. Evaporator and condenser heat transfer coefficient data are presented and the trends are examined in the context of the expected effect of the Marangoni mechanisms on heat transfer. Heat pipe design features that take maximum advantage of Marangoni effects are described and the application of these types of heat pipes to electronics cooling and heat removal from concentrating photovoltaic systems is discussed.

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Evaluation of the uncertainty associated with sample holders in NAA measurements in LAN/IPEN

Brazilian Journal of Radiation Sciences ◽

10.15392/bjrs.v7i2a.676 ◽

2019 ◽

Vol 7 (2A) ◽

Author(s):

Guilherme Soares Zahn ◽

Regina Beck Ticianelli ◽

Mitiko Saiki ◽

Frederico Antonio Genezini

Keyword(s):

Stainless Steel ◽

Neutron Activation Analysis ◽

Neutron Activation ◽

Gamma Rays ◽

Experimental Error ◽

Steel Sample ◽

Low Energy ◽

Stainless Steel Sample ◽

Gamma Emission ◽

Energy Gamma

In IPEN’s Neutron Activation Laboratory (LAN/IPEN), thin stainless steel sample holders are used for gamma spectrometry in NAA measurements. This material is very practical, but its chemical composition may be troublesome, as it presents large amounts of elements with intermediate atomic number, with attenuation factors for low-energy gamma-rays that must not be neglected. In this study, count rates obtained using different sample holders were compared. To accomplish that, an Am-241 source, with 59-keV gamma emission, was used so that low-energy gamma attenuation differences can be determined. Moreover, in order to study the energy dependence of these differences, a Ho-166m source was also used. From these results, it was possible to analyze the experimental error associated to the variations between sample holders, with the aim of introducing an addictive term to the uncertainty analysis of comparative Neutron Activation Analysis results.

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