Heat transfer in composite materials disintegrating under high-rate one-sided heating

1993 ◽  
Vol 65 (6) ◽  
pp. 1149-1155
Author(s):  
K. B. Isaev
Materials ◽  
2021 ◽  
Vol 14 (23) ◽  
pp. 7299
Author(s):  
Alejandro Pereira ◽  
Alberto Tielas ◽  
Teresa Prado ◽  
Maria Fenollera ◽  
José Antonio Pérez

The new requirements in different sectors, such as aerospace, automotive and construction, for lightweight materials have led to an increase in demand for composite materials suitable for use in high rate production processes, such as plastic injection. This makes it necessary to look for matrices and reinforcements that, in addition to being compatible with each other, are also compatible with the injection process. It is in this area of research where the work presented here arises. To meet the two requirements mentioned above, this study contemplates a battery of composite materials obtained by combining PA66 and fiberglass, in different proportions and configuration, both for the preparation of the matrix and for reinforcement. For the elaboration of the matrix, two options have been evaluated, PA66 and PA66 reinforced at 35% with short glass fibre. To obtain reinforcement, six different options have been evaluated; two conventional fiberglass fabrics (each with different density) and four hybrid fabrics obtained from the previous ones by adding PA66 in different configurations (two over-stitched fabrics and two other fabrics). The different composite materials obtained were validated by means of the corresponding adhesion, peeling and resistance tests.


Author(s):  
Chunyu Xu ◽  
Junhua Lin ◽  
Wenhao Liu ◽  
Yuanbiao Zhang

This paper predict and effectively control the temperature distribution of the steady-state and transient states of anisotropic four-layer composite materials online, knowing the density, specific heat, heat conductivity and thickness of the composite materials. Based on the transfer function, a mathematical model was established to study the dynamic characteristics of heat transfer of the composite materials. First of all, the Fourier heat transfer law was used to establish a one-dimensional Fourier heat conduction differential equation for each composite layer, and the Laplace transformation was carried out to obtain the system function. Then the approximate second-order transfer function of the system was obtained by Taylor expansion, and the Laplace inverse transformation was carried out to obtain the transfer function of the whole system in the time domain. Finally, the accuracy of the simplified analytical solutions of the first, second and third order approximate transfer functions was compared with computer simulation. The results showed that the second order approximate transfer functions can describe the dynamic process of heat transfer better than others. The research on the dynamic characteristics of heat transfer in the composite layer and the dynamic model of heat transfer in composite layer proposed in this paper have a reference value for practical engineering application. It can effectively predict the temperature distribution of composite layer material and reduce the cost of experimental measurement of heat transfer performance of materials.


Author(s):  
A. A. Ameri ◽  
E. Steinthorsson

The rate of heat transfer on the tip of a turbine rotor blade and on the blade surface in the vicinity of the tip, was successfully predicted. The computations were performed with a multiblock computer code which solves the Reynolds Averaged Navier-Stokes equations using an efficient multigrid method. The case considered for the present calculations was the SSME (Space Shuttle Main Engine) high pressure fuel side turbine. The predictions of the blade tip heat transfer agreed reasonably well with the experimental measurements using the present level of grid refinement. On the tip surface, regions with high rate of heat transfer was found to exist close to the pressure side and suction side edges. Enhancement of the heat transfer was also observed on the blade surface near the tip. Further comparison of the predictions was performed with results obtained from correlations based on fully developed channel flow.


2015 ◽  
Vol 1124 ◽  
pp. 89-96
Author(s):  
Jan Prokeš

The paper is focused on the use of advanced composite materials in the real application areas of buildings exposed to extreme environmental stress. The paper describe properties of composite rebar, especially with regards to long-term resistance to chemical and corrosion attack, minimization of heat transfer or resistance in construction with reduced concrete cover. The paper also presents behavior of composite rebar and concrete samples with composite reinforcement during loading and fire tests.


2014 ◽  
Vol 592-594 ◽  
pp. 1794-1800
Author(s):  
G. Vijayakumar ◽  
Ashwani Kumar Kachroo

Missiles fly at supersonic and hypersonic speeds. Airframe forms the aerodynamic shape of the missile and houses several components essential for mission with suitable structural supports. The missile airframe is subjected to high rate of heating caused by kinetic heating due to very high vehicle speed. Heat transfer analysis of the missile airframe structure is required to be performed for wall temperature predictions to select the material of missile construction with suitable wall thickness and also to check design adequacy for ensuring the safe operation in the severe thermal environment experienced during flight. This paper describes the methodology of evaluation of heat flux distribution over missile wall, prediction of missile wall temperature distribution considering airframe as heat sink and validation of the methodology against flight data. Heat flux has been estimated using classical engineering methods for both stagnation as well as off-stagnation regions including the effect of angle of attack, rarified flow, thermal radiation and solar heating. Transient three dimensional heat transfer analysis with convective and radiative boundary conditions has been carried out for predicting the missile wall temperature profiles. Parametric study has been carried out, considering various parameters such as material of construction, thickness and time duration. The prediction methodology has been validated and a close match is observed between the predictions and flight data.


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