On the Minimum Film Boiling Conditions for Spherical Geometries

1980 ◽  
Vol 102 (2) ◽  
pp. 335-341 ◽  
Author(s):  
F. S. Gunnerson ◽  
A. W. Cronenberg
Keyword(s):  
Experimental Data ◽  
Heat Flux ◽  
Flat Plate ◽  
Analytical Method ◽  
Boiling Point ◽  
Film Boiling ◽  
Heater Surface ◽  
Wide Range ◽  
Minimum Heat ◽  
Good Agreement

An analytical method is presented for predicting the minimum heater temperature and the minimum heat flux at the onset of film boiling for spherical and flat plate heaters in saturated and subcooled liquids. Consideration is given to a variety of factors known to affect the minimum film boiling point, including transient liquid-heater contact, interfacial wettability, heater geometry, and liquid subcooling. The theoretical correlations developed are the first known predictions for spherical geometries. A comparison of theory with experimental data indicates good agreement for the minimum heat flux and the minimum film boiling temperature. Results indicate that the minimum conditions may span a wide range depending upon the thermophysical nature of the heater surface and the boiling liquid.

The Dominant Unstable Wavelength and Minimum Heat Flux During Film Boiling on a Horizontal Cylinder

1964 ◽  
Vol 86 (2) ◽  
pp. 220-225 ◽  
Author(s):  
J. H. Lienhard ◽  
P. T. Y. Wong
Keyword(s):  
Surface Tension ◽  
Heat Flux ◽  
Flat Plate ◽  
Transverse Direction ◽  
Horizontal Cylinder ◽  
Heat Fluxes ◽  
Taylor Instability ◽  
Film Boiling ◽  
Minimum Heat ◽  
Effect Of Surface

Predictions of the dominant unstable wavelength and the minimum heat flux during film boiling above a flat plate are found to be inapplicable in the case of boiling on small wires. New expressions are developed for the case of a horizontal cylinder, by accounting for the effect of surface tension in the transverse direction upon the Taylor instability of the interface. Original measurements of wavelengths and minimum heat fluxes on small wires are also provided. These data support the predictions.

Microchannel Condensation: Comparison of Annular Laminar Flow Theory With Detailed Measurements

2013 ◽  
Author(s):  
H. S. Wang ◽  
J. W. Rose
Keyword(s):  
Experimental Data ◽  
Heat Flux ◽  
Laminar Flow ◽  
Local Heat ◽  
Experimental Investigations ◽  
Experimental Conditions ◽  
Two Fluids ◽  
Wide Range ◽  
Local Heat Flux ◽  
Good Agreement

Detailed experimental investigations of condensation in microchannels where local heat flux and surface temperature were measured along the channel are compared with theoretical results for the special case of annular, laminar flow. The theoretical model includes surface tension driven transverse flow towards the corners of the channel as well as shear stress driven streamwise flow in an otherwise Nusselt treatment. The theory has no empirical input. When distributions along the channel of the local vapor and wall temperatures are given, local heat flux and heat-transfer coefficient, as well as local vapor quality, may be calculated. Such detailed experimental data have only recently become available. Strict implementation of the theory requires that the onset of condensation occurs within the channel, i.e. the vapor is saturated or superheated at the inlet. The comparisons show remarkably good agreement with the experimental data for two fluids and covering a wide range of experimental conditions.

Combustion Simulation of Propane/Oxygen (With Nitrogen/Argon) Mixtures Using Rate-Controlled Constrained-Equilibrium

2018 ◽  
Vol 141 (2) ◽  
Author(s):  
Guangying Yu ◽  
Hameed Metghalchi ◽  
Omid Askari ◽  
Ziyu Wang
Keyword(s):  
Experimental Data ◽  
Energy System ◽  
Kinetic Mechanism ◽  
Chemical Kinetic ◽  
Oxygen Mixture ◽  
Free Valence ◽  
Wide Range ◽  
Constrained Equilibrium ◽  
Rate Controlled ◽  
Good Agreement

The rate-controlled constrained-equilibrium (RCCE), a model order reduction method, has been further developed to simulate the combustion of propane/oxygen mixture diluted with nitrogen or argon. The RCCE method assumes that the nonequilibrium states of a system can be described by a sequence of constrained-equilibrium states subject to a small number of constraints. The developed new RCCE approach is applied to the oxidation of propane in a constant volume, constant internal energy system over a wide range of initial temperatures and pressures. The USC-Mech II (109 species and 781 reactions, without nitrogen chemistry) is chosen as chemical kinetic mechanism for propane oxidation for both detailed kinetic model (DKM) and RCCE method. The derivation for constraints of propane/oxygen mixture starts from the eight universal constraints for carbon-fuel oxidation. The universal constraints are the elements (C, H, O), number of moles, free valence, free oxygen, fuel, and fuel radicals. The full set of constraints contains eight universal constraints and seven additional constraints. The results of RCCE method are compared with the results of DKM to verify the effectiveness of constraints and the efficiency of RCCE. The RCCE results show good agreement with DKM results under different initial temperature and pressures, and RCCE also reduces at least 60% CPU time. Further validation is made by comparing the experimental data; RCCE shows good agreement with shock tube experimental data.

MAGNETIC BODY FORCE

2005 ◽  
Vol 19 (07n09) ◽  
pp. 1205-1208 ◽  
Author(s):  
A. F. BAKUZIS ◽  
KEZHENG CHEN ◽  
WEILI LUO ◽  
HONGZHANG ZHUANG
Keyword(s):  
Experimental Data ◽  
Magnetic Fluid ◽  
Magnetic Force ◽  
Body Force ◽  
Wide Range ◽  
Magnetic Body Force ◽  
Good Agreement

We have studied magnetic force on sperical magnetic fluid samples with a wide range of concentrations by pendulum method. The results demonstrate good agreement with Kelvin body force and show that other force expressions clearly deviate from experimental data for large sussceptibility values.

Free Convection Film Boiling Heat Transfer From a Rotating Surface

1992 ◽  
Vol 114 (3) ◽  
pp. 695-702 ◽  
Author(s):  
J. Orozco ◽  
H. Francisco
Keyword(s):  
Free Convection ◽  
Surface Flux ◽  
Film Boiling ◽  
Integral Approach ◽  
Vapor Film ◽  
Experimental Facility ◽  
Layer Model ◽  
Rotating Surface ◽  
Minimum Heat ◽  
Good Agreement

A boundary layer model of laminar, subcooled, free convection film boiling from a rotating sphere has been developed. The conservation equations for the vapor and liquid were simplified, transformed into ordinary differential equations using an integral approach, and solved numerically. The theoretical variation of vapor film thickness with heater temperature and the resulting boiling fluxes were investigated. An experimental facility was built for the purpose of verifying the validity of the theoretical model and good agreement was found between the model and the experimental data at low rpm. The instability of the vapor film near the minimum heat flux for a rotating surface flux was also investigated.

Power–gap relationships in low consistency refining

2019 ◽  
Vol 34 (1) ◽  
pp. 36-45 ◽  
Author(s):  
Jorge Enrique Rubiano Berna ◽  
Mark Martinez ◽  
James Olson
Keyword(s):  
Experimental Data ◽  
Force Sensor ◽  
Pilot Scale ◽  
Mill Scale ◽  
Control Power ◽  
Wide Range ◽  
Theoretical Assumptions ◽  
Mechanical Pulps ◽  
The Relationship ◽  
Good Agreement

Abstract Distance between stationary and rotating refining plates, gap, has a direct and significant impact on refining power. Gap is almost universally used to control power in low consistency refining operations. The relationship between power and gap are affected by refiner size, pulp type, plate pattern and refining conditions. In this study, a correlation was developed to describe the power–gap relationships at a wide range of refining conditions and furnish. The correlation was developed using pilot-scale refining data of mechanical pulps. Results showed that a properly defined dimensionless power number is suitable to describe refining power as well as to compare different refiners under the same grounds. The developed correlation was also used to predict mill-scale refining data showing good agreement with between predicted and measured values. Finally, experimental data from force sensor measurements supports the correlation’s theoretical assumptions.

VLE Determination of Carbon Dioxide Loaded Aqueous Alkanolamine Mixtures Using Modified Kent Eisenberg Model

2017 ◽  
Vol 231 (11-12) ◽  
Author(s):  
Humbul Suleman ◽  
Abdulhalim Shah Maulud ◽  
Zakaria Man
Keyword(s):  
Experimental Data ◽  
Carbon Dioxide ◽  
Model Parameters ◽  
Thermodynamic Models ◽  
Carbon Dioxide Absorption ◽  
Proposed Model ◽  
Wide Range ◽  
Experimental Values ◽  
Good Agreement

AbstractA computationally simple thermodynamic framework has been presented to correlate the vapour-liquid equilibria of carbon dioxide absorption in five representative types of alkanolamine mixtures. The proposed model is an extension of modified Kent Eisenberg model for the carbon dioxide loaded aqueous alkanolamine mixtures. The model parameters are regressed on a large experimental data pool of carbon dioxide solubility in aqueous alkanolamine mixtures. The model is applicable to a wide range of temperature (298–393 K), pressure (0.1–6000 kPa) and alkanolamine concentration (0.3–5 M). The correlated results are compared to the experimental values and found to be in good agreement with the average deviations ranging between 6% and 20%. The model results are comparable to other thermodynamic models.

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