Nucleate Boiling Performance of Azeotropic Binary Mixtures in a Saturate Pool Boiling System

2010 ◽  
Author(s):  
Kunihito Matsumura ◽  
Fumito Kaminaga
Keyword(s):  
Heat Transfer ◽  
Ethylene Glycol ◽  
Propylene Glycol ◽  
Binary Mixtures ◽  
Pure Water ◽  
Prediction Method ◽  
Nucleate Boiling ◽  
Transfer Coefficients ◽  
Process Industries ◽  
Nucleate Boiling Heat Transfer

Nucleate boiling of binary mixtures is of particular importance in chemical and process industries. The purpose of the present study is to provide experimental data and prediction method for nucleate boiling heat transfer in two types of anti-freeze solutions, Propylene-glycol (PG)/water and Ethylene-glycol (EG)/water, under atmospheric pressure. The experiments were performed in a saturated condition. The concentrations of solutions are varied from 10 to 40 wt%. It was found that the heat transfer coefficient gradually decreases as increasing the addition of anti-freeze. An addition of small amount of propylene-glycol and ethylene-glycol to water also decreases the CHF value far below that of pure water. It is concluded that the correlation proposed by Fujita for several binary mixtures can well predict the heat transfer coefficients within almost ±5% accuracy for every concentration of mixture solutions.

Heat Transfer Characteristics and Bubble Behaviors During Nucleate Flow Boiling for Sodium Chloride Solution

2019 ◽  
Author(s):  
Junping Gu ◽  
Guoli Tang ◽  
Yuxin Wu ◽  
Junfu Lyu ◽  
Hairui Yang ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Boiling Heat Transfer ◽  
Saline Solution ◽  
Flow Boiling ◽  
Pure Water ◽  
Nucleate Boiling ◽  
Transfer Coefficients ◽  
Heat Transfer Coefficients ◽  
Nucleate Boiling Heat Transfer

Abstract Deep understanding of nucleate boiling heat transfer mechanism of saline solution is of great importance for the design and safe operation of steam generation equipment. In this paper, the nucleate flow boiling process of saline solution in a vertical heated pipe was experimentally studied within the concentration range of 0 % ∼ 6 %. In order to realize the visualization, the vertical heated pipe was made of transparent silica glass and a transparent ITO heater was used to provide energy for boiling. The high-speed high-resolution camera was used to capture the vapor-liquid two-phase flow structure. The bubble behaviors such as bubble departure diameter, bubble departure frequency, bubble growth time and waiting time were investigated under different operating conditions. The experimental results showed that the heat transfer deterioration did not occur within the solution concentration of 6% in this work. Under some low heat flux conditions, the heat transfer coefficients of solution can be higher than those of pure water. The reason for this phenomenon can be explained by the different bubble behaviors. Comparing to pure water, the bubble departure diameter of saline solution is bigger and bubble departure frequency is lower. The influences of operating parameters, including concentration, mass flux (200 kg/m2s ∼ 600 kg/m2s), heat flux (30 kW/m2 ∼ 180 kW/m2) and subcooling of fluid (5 K ∼ 35 K), on the nucleate boiling heat transfer coefficients and bubble parameters were comprehensively studied.

Pool Boiling Heat Transfer From Plain and Microporous, Square Pin Finned Surfaces in Saturated FC-72

1999 ◽  
Author(s):  
K. N. Rainey ◽  
S. M. You
Keyword(s):  
Heat Transfer ◽  
Boiling Heat Transfer ◽  
Large Scale ◽  
Pool Boiling ◽  
Nucleate Boiling ◽  
Small Scale ◽  
Surface Microstructure ◽  
Transfer Coefficients ◽  
Microporous Coating ◽  
Nucleate Boiling Heat Transfer

Abstract The present research is an experimental study of “double enhancement” behavior in pool boiling from heater surfaces simulating microelectronic devices immersed in saturated FC-72 at atmospheric pressure. The term “double enhancement” refers to the combination of two different enhancement techniques: a large-scale area enhancement (square pin fin array) and a small-scale surface enhancement (microporous coating). Fin lengths were varied from 0 (flat surface) to 8 mm. Effects of this double enhancement technique on critical heat flux (CHF) and nucleate boiling heat transfer in the horizontal orientation (fins are vertical) are investigated. Results showed significant increases in nucleate boiling heat transfer coefficients with the application of the microporous coating to the heater surfaces. CHF was found to be relatively insensitive to surface microstructure for the finned surfaces except in the case of the surface with 8 mm long fins. The nucleate boiling and CHF behavior has been found to be the result of multiple, counteracting mechanisms: surface area enhancement, fin efficiency, surface microstructure (active nucleation site density), vapor bubble departure resistance, and re-wetting liquid flow resistance.

Experimental Study of Surfactant Effects on Pool Boiling Heat Transfer

1990 ◽  
Vol 112 (1) ◽  
pp. 207-212 ◽  
Author(s):  
Ying Liang Tzan ◽  
Yu Min Yang
Keyword(s):  
Heat Transfer ◽  
Binary Mixtures ◽  
Boiling Heat Transfer ◽  
Sodium Lauryl Sulfate ◽  
Pool Boiling ◽  
Nucleate Boiling ◽  
Additive Concentration ◽  
Lauryl Sulfate ◽  
Diffusion Effect ◽  
Nucleate Boiling Heat Transfer

In the first part of this work, nucleate boiling of aqueous solutions of sodium lauryl sulfate (SLS) over relatively wide ranges of concentration and heat flux was carried out in a pool boiling apparatus. The experimental results show that a small amount of surface active additive makes the nucleate boiling heat transfer coefficient h considerably higher, and that there is an optimum additive concentration for higher heat fluxes. Beyond this optimum point, further increase in additive concentration makes h lower. In the second part of this work, nucleate boiling heat transfer rate for n-propanol-water binary mixtures with various amounts of sodium lauryl sulfate were measured in the same pool boiling apparatus. The importance of the mass diffusion effect, which is caused by preferential evaporation of the more volatile component at the vapor-liquid interface on the boiling of the binary mixture, has been confirmed. However, it is shown that the effect exerted by the addition of a surfactant dominates over the mass diffusion effect in dilute binary mixtures.

An Experimental Investigation on Flow Boiling of Ethylene-Glycol/Water Mixtures

2003 ◽  
Vol 125 (2) ◽  
pp. 317-325 ◽  
Author(s):  
Satish G. Kandlikar ◽  
Murat Bulut
Keyword(s):  
Heat Transfer ◽  
Ethylene Glycol ◽  
Binary Mixtures ◽  
Flow Boiling ◽  
Rectangular Channel ◽  
Saturation Temperature ◽  
Local Heat Transfer ◽  
Transfer Coefficients ◽  
Subcooled Flow Boiling ◽  
Subcooled Flow

Mixtures of ethylene glycol and water are used in cooling the engines in automotive applications. Heat is transferred essentially under subcooled flow boiling conditions as the mixture flows over the hot surfaces, which are at temperatures well above the local saturation temperature of the mixture. Very little information is available in the literature on the subcooled flow boiling characteristics of this mixture. The present work focuses on obtaining experimental heat transfer data for water and its mixtures containing ethylene-glycol (0 to 40 percent mass fraction, limited by the maximum allowable temperature in the present setup) in the subcooled flow boiling region. The experimental setup is designed to obtain local heat transfer coefficients over a small circular aluminum heater surface, 9.5-mm in diameter, placed at the bottom 40-mm wide wall of a rectangular channel 3-mm×40-mm in cross-section. Available models for (a) subcooled flow boiling of pure liquids and (b) saturated flow boiling of binary mixtures are extended to model the subcooled flow boiling of binary mixtures.

Theoretical Model for Nucleate Boiling Heat and Mass Transfer of Binary Mixtures

2003 ◽  
Vol 125 (6) ◽  
pp. 1106-1115 ◽  
Author(s):  
Ju¨rgen Kern ◽  
Peter Stephan
Keyword(s):  
Heat Transfer ◽  
Experimental Data ◽  
Binary Mixtures ◽  
Phase Interface ◽  
Nucleate Boiling ◽  
Interfacial Thermal Resistance ◽  
Transfer Coefficients ◽  
Total Heat Flow ◽  
Heat Transfer Coefficients ◽  
Liquid Vapor

A model is presented to calculate nucleate boiling heat transfer coefficients of binary mixtures. The model includes the governing physical phenomena, such as the variation of the phase interface curvature, the adhesion pressure between wall and liquid, the interfacial thermal resistance as well as the local variation of composition and liquid-vapor equilibrium. Marangoni convection is considered, too. The theoretical background of these phenomena is described and their implementation is explained. The model is verified by comparing calculated heat transfer coefficients of hydrocarbon mixtures with experimental data. Computational and experimental data are in good agreement. In the examples a considerable amount of the total heat flow passes through a tiny thin film area, called micro region, where the liquid-vapor phase interface is attached to the wall. Very high spatial gradients of heat flux and mixture concentration occur interacting with overall heat transfer performance.

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