scholarly journals Effect of Angle of Rotation for Fiber Aligned in a Composite Material Wall of Inclined Enclosure on Heat Transfer

2014 ◽  
Vol 92 (12) ◽  
pp. 39-50
Author(s):  
Manal AL-Hafidh ◽  
Haithem H. Muhammad ◽  
Ban B. Jawad
1992 ◽  
Vol 32 (4) ◽  
pp. 600-607 ◽  
Author(s):  
A. M. Grishin ◽  
A. N. Golovanov ◽  
A. S. Yakimov

2020 ◽  
pp. 154-160
Author(s):  
Yu.A. Gribanov ◽  
I.V. Gurin ◽  
V.V. Gujda ◽  
A.N. Bukolov ◽  
V.V. Kolosenko

The corrosion resistance of carbon-carbon composite materials (C–C composites) was studied in a corrosive media of coolant NaF+ZrF4 salt (a model heat-transfer) at 700 °С in the air flow. It has been shown that C–C composite material is resistant to the model heat-transfer even under conditions of critical temperature accident. The main mechanism that leads to the C–C composite corrosion is a mechanism of composite material oxidation due to the contact with the air. The study has evidenced that the C–C composite burn-up rate well correlates with the pyrocarbon matrix content in the composite, the matrix content increase by 2530% results in the composite corrosion resistance increase by a factor of 2–4. So, by developing corrosion-resistant carbon-carbon composites one has a problem of finding an optimum fiber-matrix ratio in the composite. It has been confirmed experimentally that by silication of C–C composites with the use of the methods which were developed in NSC KIPT it is possible to increase the service life of products under simulated accident conditions by a factor of 7–7.5.


2018 ◽  
Vol 40 (17-18) ◽  
pp. 1486-1497
Author(s):  
Rafael Chaves Deptulski ◽  
Faiza Mnasri ◽  
Mohamed El Ganaoui ◽  
Rachid Bennacer

Author(s):  
Cheng-Hsiung Kuo ◽  
Hwei-Ming Huang

This study measures the thermal conductivity of the MWNT/epoxy bulk composite material to enhance the heat transfer rates of the high power LED device. In this study, three different weight percentages (0.0 wt%, 0.3 wt% and 0.5 wt%) of MWNT/Epoxy composite and five different heat generating rates were employed for the investigation. The case of pure epoxy resins (0.0 wt%) was used as a reference. The responding time and the thermal conductivity of the composites were evaluated. The results show that the response is the fastest for composite with 0.5 wt% MWNT among three composites studied herein. The responses of the 0.3%wt and 0.5%wt composite are increased by 14.3%∼26.7% relative to that of the pure epoxy. Compare with that of the pure epoxy, the thermal conductivities for the cases with 0.3 wt% and 0.5 wt% MWNT/epoxy composite are increased by 15.9%∼44.9%. Further, the thermal conductivity does not vary with temperature for the temperature range studied herein. In the present study, the thermal conductivity of the composite material is found to increase mildly with the increasing heat generation rate.


2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Cletus Matthew Magoda ◽  
Jasson Gryzagoridis ◽  
Kant Kanyarusoke

Purpose The purpose of this paper is to validate an assumption of what to use as an effective (steady state) heat transfer coefficient of thermal conductivity for the honeycomb core sandwiched by Fiberglass face sheets composite. A one-dimensional model based on Fourier law is developed. The results are validated experimentally. Design/methodology/approach The results were obtained from the one-dimensional mathematical model of an overall or effective heat conductivity of the Honeycomb composite panel. These results were validated experimentally by applying heat flux on the specimen under controlled environment. The surface temperatures at different voltages were recorded and analysed. The skin of the sandwich composite material used in the investigation was Fiberglass sheet with a thickness of 0.5 mm at the bottom and 1.0 mm at the top surface. Both skins have a stacking sequence of zero degrees. Due to the presence of air cells in the core (Honeycomb), the model considers the conduction, convection and radiation heat transfer, across the thickness of the panel, combined as an effective conduction mode, whose value may be predicted by using the coefficient of thermal conductivity of the air based on the average temperature difference between the two skins. The experimental results for the heat transfer through the thickness of the panel provide validation of this assumption/prediction. Both infrared thermography and conventional temperature measurement techniques (thermocouples) were used to collect the data. Findings The heat transfer experiment and mathematical modeling were conducted. The data obtained were analyzed, and it was found that the effective thermal conductivity was temperature-dependent as expected. The effective thermal conductivity of the honeycomb panel was close to that of air, and its value could be predicted if the panel surface temperatures were known. It was also found that as temperature raised the variation between experimental and predicted effective air conduction raised up. This is because there was an increase in molecular diffusion and vibration. Therefore, the convection heat transfer increased at high temperatures and the air became an insulator. Originality/value Honeycomb composite panels have excellent physical and thermal properties that influence their performance. This study provides an appropriate method in determining thermal conductivity, which is one of the critical thermal properties of porous composite material. This paper also gives useful and practical data to industries that use or manufacture honeycomb composite panels.


2008 ◽  
Vol 130 (2) ◽  
Author(s):  
Kamil Kahveci ◽  
Semiha Öztuna

Magnetohydrodynamics natural convection in an inclined enclosure with a partition is studied numerically using a differential quadrature method. Governing equations for the fluid flow and heat transfer are solved for the Rayleigh number varying from 104 to 106, the Prandtl numbers (0.1, 1, and 10), four different Hartmann numbers (0, 25, 50, and 100), the inclination angle ranging from 0degto90deg, and the magnetic field with the x and y directions. The results show that the convective flow weakens considerably with increasing magnetic field strength, and the x-directional magnetic field is more effective in reducing the convection intensity. As the inclination angle increases, multicellular flows begin to develop on both sides of the enclosure for higher values of the Hartmann number if the enclosure is under the x-directional magnetic field. The vorticity generation intensity increases with increase of Rayleigh number. On the other hand, increasing Hartmann number has a negative effect on vorticity generation. With an increase in the inclination angle, the intensity of vorticity generation is observed to shift to top left corners and bottom right corners. Vorticity generation loops in each region of enclosure form due to multicelluar flow for an x-directional magnetic field when the inclination angle is increased further. In addition, depending on the boundary layer developed, the vorticity value on the hot wall increases first sharply with increasing y and then begins to decrease gradually. For the high Rayleigh numbers, the average Nusselt number shows an increasing trend as the inclination angle increases and a peak value is detected. Beyond the peak point, the foregoing trend reverses to decrease with the further increase of the inclination angle. The results also show that the Prandtl number has only a marginal effect on the flow and heat transfer.


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