Experimental Study Of Temperature Distribution Research Articles

Experimental study of temperature distribution and development of a power monitoring channel for the IPR-R1 TRIGA® research nuclear reactor

The natural convection and forced cooling experiments were conducted to confirm the cooling capability in the IPR-R1 TRIGA® nuclear research reactor. Temperature measurements were carried out in several locations such as: at the coolant inlet and outlet in the core channels, at various pool heights, and at the centre of an instrumented fuel element. The temperature monitored by the instrumented fuel element was performed with it positioned in all the core rings and at different operating powers. A new way of measuring the power released by nuclear fissions in the core using thermal processes has been developed. To monitor temperatures and power, a Data Acquisition System (DAS) was used. The information acquired during the experiments provides an exceptional representation of the IPR-R1 TRIGA® reactor’s thermal performance. The experiments confirm the efficiency of natural circulation in removing the heat produced in the reactor core by the nuclear fission.

Numerical and experimental study of temperature distribution on thermal plant coal mill walls

This article presents results of a numerical and experimental study of the temperature distribution inside and on the walls of the ventilation mill in the Kostolac B power plant, Serbia. This is very important because heat exchange between gas mixtures, ventilation mill walls and the environment, influences coal powder temperature, the combustion process, and the emission of greenhouse gases. The most complex multi‐phase model in the Euler‐Euler approach has been used through the ANSYS FLUENT code, for the numerical simulation of temperature distribution. Two ventilation mill models have been considered, one with zero wall thickness and the other one with steel walls, with and without insulation. An infrared thermographic camera was used for monitoring the temperature distribution on the outside wall of the ventilation mill housing, before insulator reparation, while after the reparation measurements were carried out at the selected points with infrared thermometer. The experimental results were used for verifying the results of the numerical simulation method as well as for detecting the damaged insulation. © 2017 American Institute of Chemical Engineers Environ Prog, 36: 1517–1527, 2017

Experimental study of temperature distribution in rubber material during microwave heating and vulcanization process

Microwave technology has been employed to heat sheet rubber, the optical fiber temperature online monitor and optical fiber temperature sensor have been employed to measure the temperature in sheet rubber. The temperature of sheet rubber increased with increase of heating time during microwave heating process in which the maximum of temperature was <100 °C and microwave vulcanization process in which the maximum of temperature was <150 °C, the curves of temperature–time presented nonlinearity. The rate of temperature rising in central zone of sheet rubber was higher than the rate of temperature rising in marginal zone of sheet rubber, and the final temperature in central zone of sheet rubber was also higher than the final temperature in marginal zone of sheet rubber. In the microwave heating and vulcanization process of sheet rubber, the maximum of rate of temperature rising and the maximum of temperature belong to the central zone of sheet rubber, so the distribution of electric field was uneven in heating chamber, which led to the uneven temperature distribution of sheet rubber. The higher electric field intensity value converges on the central zone of sheet rubber.

An experimental study of temperature distribution in an autoclave

In this work, the temperature distribution on an industrial mold tool is monitored during autoclave runs with three settings. In one of the settings, the temperature and pressure follow a scheme used in real moldings, while in the other two cases, the temperature is increased as fast as possible with and without an applied pressure. The temperature difference over the tool is relatively large and varies between 29℃ and 76℃ validating a detailed investigation of the temperature at different points. Two results of this are that positions on the up-stream side of the tool are heated faster than positions down-stream and the heating over the tool is symmetric while that within is asymmetric. Roughly estimated heat transfer coefficients reveal that the temperature ramping has no significant effect on the local heat transfer coefficients while the applied pressure more than doubled them. In addition flow field measurements with particle image velocimetry are performed, revealing a very slow flow near the roof of the autoclave and a velocity peak near the floor of it, indicating that the flow profile within the autoclave and variation in heat transfer coefficients should be considered in autoclave simulations.

Measurement of temperature distribution and evolution during surface plasma resonance heating of gold nanoshells-embedded phantom tissue

This paper presents an experimental study of temperature distribution and evolution in nanoshell colloidal solution and in phantom tissue populated with gold nanoshells under localized surface plasma resonance heating by an NIR laser. Gold nanoshells were synthesized in our laboratory and characterized using the TEM. Their optical properties were measured by a CARY 5000 photospectrometer and the localized surface plasma resonance occurs at 796nm. Two types of temperature measurement systems were used: one for the gold nanoshell colloidal solution and the other for nanoshell-populated phantom tissue. For both cases, heating was initiated by an NIR laser of 808nm. Measured data reveal that the temperature rises rapidly as a result of strong heating of gold nanoshells, which is converted from the absorbed laser energy under localized surface plasma resonance condition. Without nanoshell-mediated resonance absorption and heating, however, the temperature increase is practically negligible. The thermal transport mechanism in nanoshell-embedded tissue appears to be dominant by radiative heat transfer in the laser beam heating region but primarily by thermal conduction away from the laser beam.

Experimental study of temperature distribution on anodic surface of MEA inside a PEMFC with parallel channels flow bed

The temperature distribution on membrane electrode assembly (MEA) surface is very important to the performance, lifetime and reliability of proton exchange membrane fuel cells (PEMFCs). With thermal imaging technology and the self-designed fuel cell, the measurement of whole temperature fields on anode MEA surface under parallel channels was achieved experimentally at non-humidification conditions. The results show that the temperatures in the middle channels are higher than that in other channels and the temperatures in the middle section appear higher than that in other sections for each channel. The non-uniformity of flow distribution in parallel channel is one of the key factors causing the non-uniformity of temperature field. It implies that the uniformity of flow field should be concerned for improving the uniformity of temperature distribution. Experimental results also appear that the temperature of MEA, non-uniformity of temperature distribution on the MEA surface and the fuel cell temperature increase with the loaded current density.

Analysis of Temperature Distribution and SEM Images of Microwave Freeze Drying Banana Chips

Compared with freeze drying (FD), microwave freeze drying (MFD) using microwave as the heating source can accelerate the drying rate of bananas. This paper presents the results of an experimental study of temperature distribution during the process of MFD banana chips. The results show that the temperature distribution is uniform during the sublimation drying stage, but not at the start of the desorption stage of drying; this phase is prone to generate hot spots, which are brought about by the localized melting of ice crystals not removed in the sublimation stage and the absorption of excess microwave by sorbed water. Comparison of scanning electron microscope micrographs of FD and MFD samples shows that the major dissimilarity between the two samples is in their pore sizes.

Computational and Experimental Study of Temperature Distribution and Residual Stress in Butt-Joint TIG Welds

This work conducted a non-linear finite element model associated with arc efficiency to simulate the temperature distribution and residual stress. A three-dimensional finite element analysis of temperature and stress in butt-joint TIG welds was performed using commercial software ANSYS. This model includes adjusting Gaussian distribution heat flux, alternating temperature dependent material properties, and managing thermal elasto-plastic material behavior. Computational results for both the temperature distribution and the residual stress are compared with available experimental data to confirm the accuracy of this technique. The simulated results of temperature distribution and residual stress are in good agreement with corresponding experimental data. The greatest value of this work does not lie in its ability to predict the magnitude and distribution of weld temperature and residual stress. Rather, this work proposed that prediction errors in a finite element model can be eliminated by modifying the arc power distribution function.

Experimental Study of Temperature Distribution and Flame Spread Over an Inert Porous Bed Wetted with Liquid Fuel

A combined experimental and modelling study was carried out to investigate the flame spread phenomenon over a porous bed wetted with finite quantity of super-flash liquid fuel. Measurements included flame spread rate, temperature distribution, and visual observation. Sand particles ranging from 0.5 to 5 mm and Propanol (flash point 12 °C) were used as porous bed and liquid fuel, respectively.Results corresponding to the rate of flame spread show that regardless of airflow speed and/or direction the rate of flame spread decreases as either the bed depth or particle size increases, however the flame spread deceleration rate is more distinct under opposed airflow.Temperature measurements and mathematical modelling results indicated the existences of three different temperature regions in the bed. The magnitude of temperature in upper region was significantly larger than those of the lower region. The modelling results were in good agreement with the experimental data.

Experimental study of temperature distribution and local heat flux for turbulent Rayleigh–Bénard convection of air in a long rectangular enclosure

Measurements of temperature distribution and local heat flux were performed in a rectangular Rayleigh–Bénard (RB) cell with aspect ratios Γ x = 5 and Γ y = 1 using air as the working fluid. The range of Rayleigh numbers was from Ra ≈ 6 × 10 7 up to Ra ≈ 6 × 10 8 and the measurements were taken at four different positions on the cooling and heating plates. The structure of the temperature profiles was analysed with the scaling to the temperature gradient at the wall γ , calculated from both global Nusselt number ( γ glob ) and the measured local heat flux density q ( γ loc ) . The measured local Nusselt number in the center of Rayleigh–Bénard cell is found to be significantly higher than the global Nusselt number, which was calculated from a heat transfer law, based on asymptotic considerations from Hoelling and Herwig [M. Hoelling, H. Herwig, Asymptotic analysis of heat transfer in turbulent RB-convection, Int. J. Heat Mass Transfer 49 (2006) 1129–1136]. Profiles scaled with γ glob agree very well with the universal asymptotic temperature profile for Ra → ∞ . Conversely, profiles scaled with γ loc have another structure. The results clearly show the difference between the temperature profiles from the theoretical model with walls of infinite extend and from the real RB-cell. In contrast to common opinion the structure of the temperature profile was found to consist of three different behaviors. It has been observed for all profiles a linear behavior in the viscous sublayer directly on the wall, a power law in the boundary layer and a logarithmic function in the overlap layer.

Experimental study of temperature distribution in the vicinity of film boiling

The transition of nucleate to film boiling on a flat surface is studied experimentally. In the vicinity of the boundary of a propagating center of film boiling, the distributions of the temperature, of the heat flux to liquid, of the heat-transfer coefficient, and of the velocity of motion of isotherms along an exothermal surface are obtained. The experiments are carried out in liquid nitrogen. A sapphire plate with platinum temperature microsensors deposited on it by sputtering is used as a heater. The instability of the boundary of the change of the boiling modes due to the Taylor instability of the interface is found in the film boiling region, as well as an intermediate region between film and nucleate boiling, where the heat fluxes are almost three times the critical value.

Experimental study of temperature distribution in laminar tube flow of a fluid with internal heat generation

Abstract An experimental investigation of laminar fluid flow in a circular tube with internal heat generation was conducted. Wall-temperature measurements were made for a uniform internal heat source in an insulated tube, and excellent agreement was demonstrated between the experimental results and a theoretical analysis by Siegel et al.