scholarly journals Burnout Investigation of Small Diameter Tubes Immersed in Nanofluids

Energies ◽  
2021 ◽  
Vol 14 (13) ◽  
pp. 3888
Author(s):  
Janusz T. Cieśliński ◽  
Katarzyna Ronewicz
Keyword(s):  
Stainless Steel ◽  
Atmospheric Pressure ◽  
Pool Boiling ◽  
Small Diameter ◽  
Heating Surface ◽  
Experimental Measurements ◽  
Steel Tubes ◽  
Boiling Process ◽  
Heat Transfer Degradation ◽  
Simultaneous Heat

This paper deals with research into pool boiling critical heat flux (CHF) of water–Al2O3, water–TiO2 and water–Cu nanofluids on horizontal stainless steel tubes. The experiments were conducted under atmospheric pressure. Nanoparticles were tested at concentrations of 0.001%, 0.01%, 0.1% and 1% by weight. Ultrasonic vibration was used in order to stabilize the dispersion of the nanoparticles. Although dispersants were not used to stabilize the suspension, the solutions tested showed satisfactory stability. Experimental measurements were performed with stainless steel tubes of three outside diameters: 1.6, 3 and 5 mm. Enhancement of CHF was observed to be independent of the concentration and material of the nanoparticles and tube diameter, with simultaneous heat transfer degradation. Built up during the boiling process, nanolayers improve substantially the heating surface wettability. A correlation is suggested for the CHF prediction during pool boiling of nanofluids.

scholarly journals Eddy sensors for small diameter stainless steel tubes.

2011 ◽  
Author(s):  
Jack L. Skinner ◽  
Alfredo Martin Morales ◽  
J. Brian Grant ◽  
Henry James Korellis ◽  
Marianne Elizabeth LaFord ◽  
...  
Keyword(s):  
Stainless Steel ◽  
Small Diameter ◽  
Steel Tubes

Pool boiling performance of oxide nanofluid on a downward-facing heating surface

Kerntechnik ◽  
2022 ◽  
Vol 0 (0) ◽  
Author(s):  
Zhibo Zhang ◽  
Huai-En Hsieh ◽  
Yuan Gao ◽  
Shiqi Wang ◽  
Jia Gao ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Surface Roughness ◽  
Stainless Steel ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Critical Heat Flux ◽  
Pool Boiling ◽  
Heating Surface ◽  
Nano Particles

Abstract In this study, the pool boiling performance of oxide nanofluid was investigated, the heating surface is a 5 × 30 mm stainless steel heating surface. Three kinds of nanofluids were selected to explore their critical heat flux (CHF) and heat transfer coefficient (HTC), which were TiO2, SiO2, Al2O3. We observed that these nanofluids enhanced CHF compared to R·O water, and Al2O3 case has the most significant enhancement (up to 66.7%), furthermore, the HTC was also enhanced. The number of bubbles in nanofluid case was relatively less than that in R·O water case, but the bubbles were much larger. The heating surface was characterized and it was found that there were nano-particles deposited, and surface roughness decreased. The wettability also decreased with the increase in CHF.

Visualization of Pool Boiling From Plain and Enhanced Structures

2005 ◽  
Author(s):  
Camil-Daniel Ghiu ◽  
Yogendra K. Joshi
Keyword(s):  
Atmospheric Pressure ◽  
Pool Boiling ◽  
Single Layer ◽  
Main Tool ◽  
Ccd Camera ◽  
Nucleate Boiling ◽  
Heat Fluxes ◽  
Working Fluid ◽  
Geometric Complexity ◽  
Boiling Process

A visualization study of pool boiling at atmospheric pressure from plain and enhanced structures was conducted with PF 5060 as working fluid. The single layer enhanced structures were fabricated in copper and were 1 mm thick. The parameters investigated in the present study are heat flux, width of microchannels and overall structure width. A monochrome CCD camera with attached magnifying lens served as the main tool for observation of the boiling process from the structures. The nucleate boiling regime for a plain surface is usually divided into two sub-regimes: the isolated bubbles regime and the coalesced bubbles regime. For enhanced structures, the increase in geometric complexity leads to different flow regimes that may establish under different heat fluxes. This study evaluates these regimes using movies and still photographs. A comparison with the plain case is made and the differences highlighted.

scholarly journals Defect detection in stainless steel tubes with AMR and GMR sensors using remote field eddy current inspection

ACTA IMEKO ◽  
2015 ◽  
Vol 4 (2) ◽  
pp. 62
Author(s):  
Artur Lopes Ribeiro ◽  
A. Lopes Ribeiro ◽  
Helena G. Ramos ◽  
Tiago J. Rocha
Keyword(s):  
Stainless Steel ◽  
Defect Detection ◽  
Eddy Current ◽  
High Sensitivity ◽  
Wheatstone Bridge ◽  
Eddy Current Testing ◽  
Experimental Measurements ◽  
Steel Tubes ◽  
Optimal Position ◽  
Current Testing

The purpose of this paper is to compare the performance of the giant magneto-resistor (GMR) and anisotropic magneto-resistor (AMR) sensors for remote field eddy current testing in stainless steel tubes. Two remote field eddy current probes were built to compare detection and characterization capabilities in standard defects like longitudinal and transverse defects. Both probes include a coil to produce a sinusoidal magnetic field that penetrates the tube wall. Each probe includes a detector with GMR and AMR sensors, where each sensor has four magneto-resistive elements configured in a Wheatstone bridge. Each sensor needs to be biased differently to operate in the high sensitivity linear mode. The description of the measurement system used to detect defects is present in the paper. For the choice of the detector optimal position, numerical simulation and experimental measurements were performed. For comparison of these sensors in defect detection using remote field eddy current testing, the experimental measurements were performed under the same conditions. The results are presented and discussed in the paper.

scholarly journals Pool Boiling in an Accelerating System

1961 ◽  
Vol 83 (3) ◽  
pp. 233-242 ◽  
Author(s):  
Herman Merte ◽  
J. A. Clark
Keyword(s):  
Heat Flux ◽  
Atmospheric Pressure ◽  
Boiling Heat Transfer ◽  
Preliminary Analysis ◽  
Pool Boiling ◽  
Heating Surface ◽  
Theoretical Description ◽  
Distilled Water ◽  
Vapor Bubbles ◽  
High Acceleration

A study is reported of the influence of system acceleration (1 to 21 g) on pool boiling heat transfer using distilled water at approximately atmospheric pressure. The acceleration of the system is such that the resulting force field is normal to the heating surface, thereby increasing the buoyant forces acting on the vapor bubbles. Heat-flux rate is varied from approximately 5000 Btu/hr-sq ft (nonboiling) to 100,000 Btu/hr-sq ft. Data are presented for the influence of subcooling with the boiling system under acceleration at the lower values of heat flux. A preliminary analysis is presented for a theoretical description of the process of boiling under the influence of high acceleration, including the simultaneous effect of natural convection.

Surface Contamination, Rejuvenation, and the Reproducibility of Results in Nucleate Pool Boiling

1981 ◽  
Vol 103 (3) ◽  
pp. 453-458 ◽  
Author(s):  
K. A. Joudi ◽  
D. D. James
Keyword(s):  
Stainless Steel ◽  
Reproducibility Of Results ◽  
Pool Boiling ◽  
Heating Surface ◽  
Corrosion Products ◽  
Surface Contamination ◽  
Nucleate Pool Boiling ◽  
Nucleation Sites

Contamination of stainless steel boiling surfaces at nucleation sites by corrosion products in water, and by oxide deposits in methanol are investigated experimentally. Reproducibility of boiling data is achieved by nitrogen sparging of test liquids and employing inert components in the apparatus. Heating surface rejuvenation is effected by boiling in refrigerant R-113. The order of testing a surface with various liquids is investigated.

scholarly journals Integration of Boiling Experiments in the Undergraduate Heat Transfer Laboratory

2003 ◽  
Vol 31 (3) ◽  
pp. 269-279 ◽  
Author(s):  
Hosni I. Abu-Mulaweh ◽  
Josué Njock Libii
Keyword(s):  
Heat Transfer ◽  
Stainless Steel ◽  
Mechanical Engineering ◽  
Engineering Students ◽  
Pool Boiling ◽  
Subcooled Boiling ◽  
Heating Source ◽  
Boiling Process ◽  
Set Up ◽  
Almost All

This paper presents two boiling experiments that can be integrated in the undergraduate heat transfer laboratory. The objective of these experiments is to enhance the understanding of the boiling process by undergraduate mechanical engineering students. These experiments expose students to several important concepts in boiling, such as subcooled boiling, modes of pool boiling, and the Leidenfrost phenomenon. The experimental set-up required to carry out these experiments is simple. It includes metallic plates such as brass, stainless steel or aluminium, a heating source such as a heating pad, thermocouples, a stopwatch, a liquid dropper, and a camera. The equipment is inexpensive and available in almost all undergraduate heat transfer laboratories.

scholarly journals Pool boiling of nanofluids on rough and porous coated tubes: experimental and correlation

2014 ◽  
Vol 35 (2) ◽  
pp. 3-20 ◽  
Author(s):  
Janusz T. Cieśliński ◽  
Tomasz Z. Kaczmarczyk
Keyword(s):  
Heat Transfer ◽  
Stainless Steel ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Pool Boiling ◽  
Correlation Equation ◽  
Distilled Water ◽  
Operating Pressure ◽  
Steel Tubes ◽  
Boiling Heat Transfer Coefficient

Abstract The paper deals with pool boiling of water-Al2O3 and water- Cu nanofluids on rough and porous coated horizontal tubes. Commercially available stainless steel tubes having 10 mm outside diameter and 0.6 mm wall thickness were used to fabricate the test heater. The tube surface was roughed with emery paper 360 or polished with abrasive compound. Aluminium porous coatings of 0.15 mm thick with porosity of about 40% were produced by plasma spraying. The experiments were conducted under different absolute operating pressures, i.e., 200, 100, and 10 kPa. Nanoparticles were tested at the concentration of 0.01, 0.1, and 1% by weight. Ultrasonic vibration was used in order to stabilize the dispersion of the nanoparticles. It was observed that independent of operating pressure and roughness of the stainless steel tubes addition of even small amount of nanoparticles augments heat transfer in comparison to boiling of distilled water. Contrary to rough tubes boiling heat transfer coefficient of tested nanofluids on porous coated tubes was lower compared to that for distilled water while boiling on porous coated tubes. A correlation equation for prediction of the average heat transfer coefficient during boiling of nanofluids on smooth, rough and porous coated tubes is proposed. The correlation includes all tested variables in dimensionless form and is valid for low heat flux, i.e., below 100 kW/m2.

Pool Boiling on Polished and Chemically Etched Stainless-Steel Surfaces

1968 ◽  
Vol 90 (2) ◽  
pp. 231-238 ◽  
Author(s):  
R. I. Vachon ◽  
G. E. Tanger ◽  
D. L. Davis ◽  
G. H. Nix
Keyword(s):  
Heat Transfer ◽  
Surface Roughness ◽  
Stainless Steel ◽  
Atmospheric Pressure ◽  
Pool Boiling ◽  
304 Stainless Steel ◽  
Distilled Water ◽  
Preparation Technique ◽  
Nucleation Sites ◽  
Steel Surfaces

This paper presents pool boiling data at atmospheric pressure for mechanically polished and chemically etched 304 stainless-steel surfaces in contact with distilled water. The surfaces were prepared by these techniques to produce variation in nucleation sites. Surface roughness was varied from 2–61 rms. The results show the changes in heat transfer with varying rms surface roughness and preparation technique. The Rohsenow pool boiling correlation was used to discuss the data.

Bubble Dynamics Around a Vertical Heating Element During Nucleate Pool Boiling

2003 ◽  
Author(s):  
Ahmed Z. ElGafy ◽  
Khalid Lafdi
Keyword(s):  
Growth Rate ◽  
Atmospheric Pressure ◽  
Analytical Study ◽  
Bubble Dynamics ◽  
Pool Boiling ◽  
Heating Surface ◽  
Nucleate Pool Boiling ◽  
Nucleation Sites ◽  
Surface Length ◽  
Core Volume

The present work is a description analytical study to express the bubbles dynamic during nucleate pool boiling arises from boiling of water by a vertical cylindrical heating surface under atmospheric pressure conditions. The study includes the description of bubbles formation, detachment, rise and growth around the vertical heating surface. Different formulas are considered to evaluate each of, the number of active nucleation sites on the heating surface, bubbles departure diameter along the heating surface length, bubbles frequency, bubbles rising velocity and growth rate of the diameter of the bubble through its uprising motion around the vertical heating surface. An equation for evaluating the vapor bubble core volume and its thickness around a vertical heating surface is introduced.

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