Heat Transfer From Flames Impinging on Flat and Cylindrical Surfaces

1963 ◽  
Vol 85 (1) ◽  
pp. 49-54 ◽  
Author(s):  
J. E. Anderson ◽  
E. F. Stresino
Keyword(s):  
Heat Transfer ◽  
Thermal Conductivity ◽  
Experimental Investigation ◽  
Low Temperature ◽  
Chemical Reaction ◽  
Heat Transfer Correlation ◽  
Theoretical Reasoning ◽  
Combustion Systems

An experimental investigation was made to determine the heat-transfer distribution obtained when a flame impinges on flat and cylindrical surfaces. The combustion systems studied were oxygen-hydrogen, oxygen-propane, oxygen-acetylene, and air-methane with combustion stream velocities varying from 1 ft/sec to 4600 ft/sec. Data taken with cylindrical heat-transfer surfaces are consistent with available heat-transfer correlation for low temperature gases provided the effect of chemical reaction on the thermal conductivity for flame temperatures above 3500 deg R is taken into consideration. Data taken with flat heat-transfer surfaces can be correlated quite well in a generalized curve partially based on theoretical reasoning.

scholarly journals Impact of autocatalytic chemical reaction in an Ostwald-de-Waele nanofluid flow past a rotating disk with heterogeneous catalysis

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Bai Yu ◽  
Muhammad Ramzan ◽  
Saima Riasat ◽  
Seifedine Kadry ◽  
Yu-Ming Chu ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Thermal Conductivity ◽  
Differential Equations ◽  
Chemical Reaction ◽  
Power Law ◽  
Variable Thickness ◽  
Rotating Disk ◽  
Thermal Profile ◽  
Nanofluid Flow ◽  
Power Law Index

AbstractThe nanofluids owing to their alluring attributes like enhanced thermal conductivity and better heat transfer characteristics have a vast variety of applications ranging from space technology to nuclear reactors etc. The present study highlights the Ostwald-de-Waele nanofluid flow past a rotating disk of variable thickness in a porous medium with a melting heat transfer phenomenon. The surface catalyzed reaction is added to the homogeneous-heterogeneous reaction that triggers the rate of the chemical reaction. The added feature of the variable thermal conductivity and the viscosity instead of their constant values also boosts the novelty of the undertaken problem. The modeled problem is erected in the form of a system of partial differential equations. Engaging similarity transformation, the set of ordinary differential equations are obtained. The coupled equations are numerically solved by using the bvp4c built-in MATLAB function. The drag coefficient and Nusselt number are plotted for arising parameters. The results revealed that increasing surface catalyzed parameter causes a decline in thermal profile more efficiently. Further, the power-law index is more influential than the variable thickness disk index. The numerical results show that variations in dimensionless thickness coefficient do not make any effect. However, increasing power-law index causing an upsurge in radial, axial, tangential, velocities, and thermal profile.

An Attempt to Uncouple the Effect of Coriolis and Buoyancy Forces Experimentally on Heat Transfer in Smooth Circular Tubes That Rotate in the Orthogonal Mode

1992 ◽  
Vol 114 (4) ◽  
pp. 858-864 ◽  
Author(s):  
W. D. Morris ◽  
R. Salemi
Keyword(s):  
Heat Transfer ◽  
Thermal Conductivity ◽  
Experimental Investigation ◽  
Circular Tube ◽  
Leading Edge ◽  
Combined Effect ◽  
Enhanced Heat Transfer ◽  
Coriolis Forces ◽  
Circular Tubes ◽  
Buoyancy Forces

This paper reports the results of an experimental investigation of the combined effect of Coriolis and buoyancy forces enforced convection in a circular tube that rotates about an axis orthogonal to its centerline. The experiment has been deliberately designed to minimize the effect of circumferential conduction in the tube walls by using material of relatively low thermal conductivity. A new correlating parameter for uncoupling the effect of Coriolis forces from centripetal buoyancy is proposed for the trailing and leading edges of the tube. It is demonstrated that enhanced heat transfer on the trailing edge occurs as a result of rotation. On the leading edge significant reductions in heat transfer compared to the zero rotation case can occur, but with possible recovery at high rotational speeds.

On Heat Transfer of a Two-Step Radiating Slab of Variable Thermal Conductivity

2020 ◽  
Vol 987 ◽  
pp. 137-141
Author(s):  
Ramoshweu Solomon Lebelo
Keyword(s):  
Heat Transfer ◽  
Thermal Conductivity ◽  
Chemical Reaction ◽  
Combustion Process ◽  
Variable Thermal Conductivity ◽  
Nonlinear Ordinary Differential Equation ◽  
Physical Parameters ◽  
Exothermic Chemical Reaction ◽  
Temperature Levels ◽  
Heat Transfers

An investigation of heat transfers in a combustible stockpile whose materials are of variable thermal conductivity is conducted in this article. The stockpile is modeled in rectangular slap and a two-step exothermic chemical reaction responsible for the combustion process is assumed. The reactive slab is also assumed to lose heat to the ambient by radiation. The Runge-Kutta Fehlberg (RKF45) method coupled with the Shooting technique is applied to tackle numerically the nonlinear ordinary differential equation (ODE) governing the problem. The process of heat transfer during combustion is made easy to understand by investigating effects of selected thermo-physical parameters on the system’s temperature. The results show that some thermo-physical parameters accelerate the exothermic chemical reaction and therefore raise the temperature levels, and that others help to reduce heat release rate to lower the temperature profiles. The graphs for the results are plotted and discussed accordingly.

Development of an Organic Acid Antifreeze Coolant

2014 ◽  
Vol 716-717 ◽  
pp. 130-132
Author(s):  
Jin Mao Chen ◽  
Guan Jun Leng ◽  
Ru Juan Yi ◽  
Bo Gao
Keyword(s):  
Heat Transfer ◽  
Thermal Conductivity ◽  
Low Temperature ◽  
Ethylene Glycol ◽  
Organic Acid ◽  
Environmental Protection ◽  
Inorganic Phosphate ◽  
Storage Stability ◽  
Deionized Water ◽  
Simple Preparation

An organic acid antifreeze coolant was developed in this paper which consisted mainly of deionized water, organic acid, pyrrole compound, alkali and dye. Glycol, nitrite, chromate, inorganic phosphate and other harmful additives were not contained in this formulation. The coolant overcomes the disadvantages in environmental protection, heat transfer and cost of the current technology which uses the ethylene glycol as antifreeze. The coolant has good low temperature protection, thermal conductivity and corrosion protection performance. Further more, the coolant has the advantages of simple preparation, good storage stability and a promising prospects.

Experimental Investigation on the Thermal Insulation Properties of Eic-Cellulose

2014 ◽  
Vol 554 ◽  
pp. 322-326 ◽  
Author(s):  
Wuryanti Sri ◽  
Suhardjo Poertadji ◽  
Bambang Soegijono ◽  
Nasution Henry
Keyword(s):  
Heat Transfer ◽  
Thermal Conductivity ◽  
Experimental Investigation ◽  
Thermal Insulation ◽  
Cellulose Fibers ◽  
Extraction Process ◽  
Thermal Capacity ◽  
Insulation Material ◽  
Low Thermal Conductivity ◽  
Thermal Conductivities

The material with low thermal conductivity means it has a high insulating capability for reducing heat transfer. One of materials for insulation is cellulose. This study presents a insulation material of cellulose made from reeds imperata cylindrical type with the extraction process. The extraction of cellulose fibers to form a sheet by adding 3.5% Na-CMC (Sodium Cellulose Carboksil Metyl). The process of forming the sheet uses blender for 30 minutes, 45 minutes, and 60 minutes. Furthermore, each mixture are put into the oven with temperature of 40°C for 36 hours. There are three parameters will be investigated, i.e. thermal conductivity, density and thermal capacity. The results showed that the lowest and the highest of thermal conductivities were 0.22 W/m K and a maximum 0.36 W/m K, respectively.

An Attempt to Experimentally Uncouple the Effect of Coriolis and Buoyancy Forces on Heat Transfer in Smooth Circular Tubes Which Rotate in the Orthogonal Mode

1991 ◽  
Author(s):  
W. D. Morris ◽  
R. Salemi
Keyword(s):  
Heat Transfer ◽  
Thermal Conductivity ◽  
Experimental Investigation ◽  
Forced Convection ◽  
Circular Tube ◽  
Leading Edge ◽  
Enhanced Heat Transfer ◽  
Coriolis Forces ◽  
Circular Tubes ◽  
Buoyancy Forces

This paper reports the results of an experimental investigation of the combined effect of Coriolis and buoyancy forces on forced convection in a circular tube which rotates about an axis orthogonal to its centre line. The experiment has been deliberately designed to minimise the effect of circumferential conduction in the tube walls by using material of relatively low thermal conductivity. A new correlating parameter for uncoupling the effect of Coriolis forces from centripetal buoyancy is proposed for the trailing and leading edges of the tube. It is demonstrated that enhanced heat transfer on the trailing edge occurs as a result of rotation. On the leading edge significant reductions in heat transfer compared to the zero rotation case can occur but with possible recovery at high rotational speeds.

An Investigation of the Unstable Oscillation Phenomenas of Two-Phase Closed Thermosyphon

2013 ◽  
Vol 668 ◽  
pp. 608-611 ◽  
Author(s):  
F.Z. Tian ◽  
Gong Ming Xin ◽  
Xin Yu Wang ◽  
Lin Cheng
Keyword(s):  
Heat Transfer ◽  
Thermal Conductivity ◽  
Experimental Investigation ◽  
Temperature Fluctuation ◽  
Low Cost ◽  
Cooling Power ◽  
Two Phase ◽  
High Heating ◽  
Sample Structure ◽  
Unstable Oscillation

Two-phase closed thermosyphon has been widely used in many heat transfer devices due to its high thermal conductivity, low cost and sample structure. During its starting and operation, there have some unstable oscillation, including dry oscillation, geyser boiling and carrying oscillation. An experimental investigation of unstable oscillation of two-phase closed thermosyphon was presented in the present paper. The experimental results showed that under the same starting power, geyser boiling is easy to achieve stability with the cooling power increasing, and under the same cooling power condition, geyser boiling could be significantly affected by the starting power. At the situation of high heating power, carrying oscillation happened easily, which caused great temperature fluctuation and disastrous effects on the heat pipe.

scholarly journals The influence of pressure on the thermal conductivity of liquid He ll

1939 ◽  
Vol 171 (945) ◽  
pp. 242-250 ◽  
Keyword(s):  
Heat Transfer ◽  
Thermal Conductivity ◽  
Mass Transfer ◽  
Heat Flow ◽  
Low Temperature ◽  
Temperature Gradient ◽  
Standard Method ◽  
The Other ◽  
Surface Films ◽  
Very High

The unusual characteristics of heat transfer in liquid He II have been reported in several recent papers. The very high thermal conductivity of the low-temperature modification of liquid helium was first noted by Keesom and Keesom (1935). It was then found by Allen, Peierls and Uddin (1937) and subsequently verified by Keesom, Keesom and Saris (1938) that the rate of transfer of heat varied with the temperature gradient. The discovery of the momentum transfer accompanying heat flow in He II which was made by Allen and Jones (1938) and the work on mobile surface films of the liquid done by Daunt and Mendelssohn (1938) show that a large part of the heat must be carried by some form of mass transfer. Several ideas and theories to explain the phenomena have been put forward by Kapitza (1938), Jones (1938), Michels, Bijl and de Boer (1938), Tisza (1938) and Keesom and Taconis (1938). The experimental evidence is as yet too meagre to prove or disprove any of the theories. It was with the intention of adding to the data already known concerning the properties of liquid He II that the present research was undertaken. The apparatus which was used is shown in fig. 1. The thermal conductivity was measured by a standard method. A constant supply of heat was supplied to one end of a long capillary containing liquid He II, and the other end was maintained at the constant temperature of the He II bath. Temperatures were observed at two points along the capillary.

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