Heat Transfer From Extended Surfaces And Combined Convection Radiation Analysis

The black, silver and white cans all started with an interior temperature of 80°C but concluded with interior temperatures of 40°C, 33°C and 32°C respectively. At any given point in the experiment you could view the results and have them reflect the final result, there was no great fluctuation in the heat transfer, it remained consistent throughout the

if there no flow, there is no differential temperature, the faster the gas flows the more heat gas molecules absorb

Next are the methods that where done in this experiment. The materials used where: A digital Thermometer, human

3. When heat flows from a warm object in contact with a cool object, do both objects undergo the same amount of temperature change?

Heat transfer processes are prominent in engineering due to several applications in industry and environment. Heat transfer is central to the performance of propulsion systems, design of conventional space and water heating systems, cooling of electronic equipment, and many manufacturing processes (Campos 3).

The purpose of this experiment is to study the effects of how fins affect the thermal resistance and properties of an object. The experiment conducted analysis on three cases for three different plates which were subjected to convection from a blower. The first plate had two fins, the second had one fin and the third had no fins. Each plate had an electrically generated heater in the base. Each plate also started in the same initial conditions. Each plate was well insulated around the base, was painted black and assumed to be a black body with an emissivity of 1. For each case, the wattage of the heater was recorded initially and finally to determine the average heat generation. A constant air flow was applied to each plate by a blower. The methods for recording data involved using thermocouples to analyze the temperature over time. Once a steady state temperature was observed in LabVIEW, then a thermal camera was used to obtain the infrared profiles for each plate. The methods involved in interpreting the infrared profiles consisted of using software to determine the temperatures at the plate, fin base and fin tip. The experiment was conducted in order to gain insight on how fins affect thermal resistance of an object. General assumptions include steady state, constant thermal properties, constant freestream velocity of air, identical fins, negligible surface area from thermocouples on fins, black body, neglect conduction resistance form black paint and

Hachicha [17] developed a numerical model of a parabolic trough receiver for thermal and optical analysis. All the heat energy balance correlations are used in order to perform the model. A numerical -geometric method is used to calculate the heat flux around the receiver. The model is verified by experimental data done by Sandia National Laboratories. The results indicate some differences at high temperatures, and these discrepancies are due to optical properties of the collector. Other reason why the comparison is not accurate is that there is some error using the equations related to heat transfer coefficient. In addition to that, another validation for the proposed model is done with experimental data of un-irradiated receivers. The results indicate that the proposed model can well estimate the heat loss and temperature.

Rayleigh-Bénard convection experiments used fluids heated from below with a confining plate on the top surface. In case of Bénard-Marangoni convection arrangement, the top surface does not have a confining plate and is free to move and deform.

The figure 2.1 (a) is a 2D representation of the actual system.It is composed by a copper

Many engineering systems during their operation generate heat. If this generated heat is not dissipated rapidly to its surrounding atmosphere, this may cause rise in temperature of the system components. This by-product cause serious overheating problems in electronic system and leads to whole system failure, so the generated heat within the system must be rejected to its surrounding to maintain the system at recommended or limited temperature for its efficient and proper working. The techniques used in the cooling of high power density electronic devices vary widely, depending on the application and the required cooling capacity. The heat generated by the electronic components has to pass through a complex network of thermal resistances to the environment. The enhancement of heat transfer is an important subject of thermal engineering. Extended surfaces that are well known as fins are commonly used to enhance heat transfer in many industries. Pin fin is one of them. Heat transfer rate is increased by using natural, forced or mixed convection. But now a day’s application of natural convection to the cooling of electrical and electronic equipment has received a considerable attention over the past years. It doesn‘t require either a fan or a blower, it is free of maintenance, zero power consumption, is low cost, the noise level is reduced and also the cleanliness of the system is improved. These features of natural convection cooling play an important role in the electrical as

Thermal management in the supersonic combustion chambers subjected to high heat fluxes is vital for maintaining their integrity. At high temperatures ordinary materials cannot sustain the high heat loads. On the other hand, the prevailing high temperature gradients, necessitates the provision for expansion to avoid build of thermal stresses for the integration. Hence, thermal management needs a holistic approach encompassing the areas of material selection, heat transfer and structural integration. The current state of art research is focused on achieving this by active cooling through endothermic fuel, which is used as a coolant due to the advantages such as reduced weight and improved heat sink capacities. Particularly the space applications pose serious limitations on the weight. 1D thermo-structural hand calculations can be easy point to start with to arrive at the optimized shape of the single actively cooled channel. But the underlying assumptions and owing to the 1D nature of the such calculations, pose limitation towards understanding the behavior of the active panel as a whole and achieving the practical integration strategy. Therefore, there is need to perform 3D CFD and FEA thermo-structural analysis of the active panel structure. This paper extends upon the approach of 1D analytical material selection methodology through weight optimization followed by rigorous CFD and FEA analysis to understand and device ways for structural integration for long

The critical heat flux (CHF) condition is characterized by a sharp reduction of the local heat transfer coefficient that results from the replacement of liquid by vapor adjacent to the heat transfer surface .The occurrence of CHF is accompanied by an inordinate increase in the surface temperature for heat-flux-controlled systems, and an inordinate decrease in the heat transfer rate for temperature-controlled systems. The CHF condition is

The main objectives of this experiment are to determine the combined heat transfer (Qr + Qc) from a horizontal cylinder in natural convection over a wide range of power inputs and surface temperature. Also to compare between convection and radiation heat transfer and between Hc and Hr. Moreover, to determine the effect of forced convection and to show the relation between air velocity and surface temperature for forced convection. And demonstrate that the local heat transfer coefficient varies around the circumference of a horizontal cylinder when subjected to forced convection.

The study of free convection flow and heat transfer under the influence of inclined magnetic field has received considerable interest due to its wide application in geophysics, astrophysics and various engineering and industrial processes such as thermal insulation, drying of porous solid materials, manufacturing of ceramic, heat exchanges, stream pipes, water heaters, electrical conductors , enhanced oil recovery, polymer production, packed-bed catalytic reactors, food processing, cooling of nuclear reactors, underground energy transport, magnetized plasma flow, high speed plasma wind, cosmic jets and stellar system. Several studies have been reported on the effect of inclined magnetic field on fluid flow in different physical situations.

Heat transmission is the process through which heat is transferred in swap of thermal energy that exists between the physical systems, depending on the pressure and temperature by dissipating heat. The essential modes of transferring the heat are convection, conduction or diffusion and radiation. Heat is transferred from region of high temperature to low temperature region.