Temperature Variation History Prediction of Fully-Closed Adhesive Joint in Curing Process

2010 ◽  
Vol 44-47 ◽  
pp. 394-399
Author(s):  
Chu Chen ◽  
Zhi Guo Lu ◽  
Jian Ping Lin
Keyword(s):  
Heat Transfer ◽  
Heat Capacity ◽  
Adhesive Joint ◽  
Temperature History ◽  
Curing Process ◽  
Transfer Coefficients ◽  
Temperature Prediction ◽  
Heat Transfer Coefficients ◽  
Heat Transfer Theory ◽  
History Of

To describe the heat transfer of fully-closed adhesive joint in curing process, adhesive joint, enclosure for closing joints and its inner air are simplified as a multi-lumped-heat-capacity system neglecting the heat from adhesive chemical reaction. Based on heat transfer theory, a temperature prediction model of fully-closed joint was proposed. Combining experimental temperature history of the joint with finite difference method, the combined heat transfer coefficients of adhesive under different curing temperatures were obtained according to Newton's heat transfer formula. And the model was validated by the experiments. The results revealed that the model can be used to predict the temperature of fully-closed adhesive joint in curing process.

scholarly journals Solving the inverse heat conduction problem using NVLink capable Power architecture

2017 ◽  
Vol 3 ◽  
pp. e138 ◽  
Author(s):  
Sándor Szénási
Keyword(s):  
Heat Transfer ◽  
Data Transfer ◽  
Heat Conduction Problem ◽  
Inverse Heat Conduction Problem ◽  
Transfer Coefficients ◽  
Heat Transfer Coefficients ◽  
Inverse Heat Transfer ◽  
Long Time ◽  
History Of ◽  
The Cost

The accurate knowledge of Heat Transfer Coefficients is essential for the design of precise heat transfer operations. The determination of these values requires Inverse Heat Transfer Calculations, which are usually based on heuristic optimisation techniques, like Genetic Algorithms or Particle Swarm Optimisation. The main bottleneck of these heuristics is the high computational demand of the cost function calculation, which is usually based on heat transfer simulations producing the thermal history of the workpiece at given locations. This Direct Heat Transfer Calculation is a well parallelisable process, making it feasible to implement an efficient GPU kernel for this purpose. This paper presents a novel step forward: based on the special requirements of the heuristics solving the inverse problem (executing hundreds of simulations in a parallel fashion at the end of each iteration), it is possible to gain a higher level of parallelism using multiple graphics accelerators. The results show that this implementation (running on 4 GPUs) is about 120 times faster than a traditional CPU implementation using 20 cores. The latest developments of the GPU-based High Power Computations area were also analysed, like the new NVLink connection between the host and the devices, which tries to solve the long time existing data transfer handicap of GPU programming.

Optimum Geometry of Plate Fins

2012 ◽  
Vol 134 (8) ◽  
Author(s):  
R. Karvinen ◽  
T. Karvinen
Keyword(s):  
Heat Transfer ◽  
Convection Heat Transfer ◽  
Transfer Coefficients ◽  
Maximum Heat ◽  
Geometrical Properties ◽  
Heat Transfer Coefficients ◽  
Fixed Volume ◽  
Maximum Heat Transfer ◽  
Heat Transfer Theory ◽  
Approximate Analytical Solutions

A method and practical results are presented for finding the geometries of fixed volume plate fins for maximizing dissipated heat flux. The heat transfer theory used in optimization is based on approximate analytical solutions of conjugated heat transfer, which couple conduction in the fin and convection from the fluid. Nondimensional variables have been found that contain thermal and geometrical properties of the fins and the flow, and these variables have a fixed value at the optimum point. The values are given for rectangular, convex parabolic, triangular, and concave parabolic fin shapes for natural and forced convection including laminar and turbulent boundary layers. An essential conclusion is that it is not necessary to evaluate the convection heat transfer coefficients because convection is already included in these variables when the flow type is specified. Easy-to-use design rules are presented for finding the geometries of fixed volume fins that give the maximum heat transfer. A comparison between the heat transfer capacities of different fins is also discussed.

Numerical Simulation on the Temperature Field of Steel 1045 Quenched by Different Hardening Media

2013 ◽  
Vol 444-445 ◽  
pp. 1222-1228
Author(s):  
Jian Bin Xie ◽  
Chang Chang Wu ◽  
Jing Fan ◽  
Miao Fu ◽  
Deng Feng Hu
Keyword(s):  
Heat Transfer ◽  
Finite Element ◽  
Temperature Field ◽  
Temperature Fields ◽  
Cooling Curves ◽  
Transfer Coefficients ◽  
Heat Transfer Coefficients ◽  
Heat Transfer Theory ◽  
Quenching Process ◽  
Estimate Method

Based on the experimental measured cooling curves and the boiling heat transfer theory, the inverse problem of nonlinear heat conduct equation for Steel 1045 quenched by different hardening media was established by functional analysis and finite element method, and the surface heat-transfer coefficients in continuous cooling during quenching were calculated by nonlinear estimate method. Then the constitutive model of Steel 1045 during quenching was established subsequently. Finally, the temperature field of Steel 1045 cylinder quenched by different hardening media was simulated by Finite Element Methods (FEM). Results show that the calculated temperature fields agree with the practical quenching process.

Convective Heating at the Deflecting Surface of a Rocket Launch-Pad

1967 ◽  
Vol 71 (679) ◽  
pp. 469-475 ◽  
Author(s):  
G. Jepps ◽  
M. L. Robinson
Keyword(s):  
Heat Transfer ◽  
Steel Plates ◽  
Convective Heating ◽  
Stagnation Temperature ◽  
Test Results ◽  
Transfer Coefficients ◽  
Exhaust Gases ◽  
Heat Transfer Coefficients ◽  
Heat Transfer Theory ◽  
The Heat Transfer Coefficient

Summary:When a large rocket or missile is fired, the hot exhaust gases must be allowed to escape without damaging structures or equipment in the vicinity of the firing area. Generally, the exhaust gases are directed harmlessly away from the launching installation by water-cooled deflecting surfaces fabricated in steel. In arid areas such as Woomera, where water is not available in large quantities, there is the possible danger that a steel efflux deflector will melt, and other materials such as refractories may be more suitable for the deflecting surface.To provide data for the design of uncooled efflux deflectors, a heating rate investigation of the Blue Streak installation at Woomera has been carried out theoretically and experimentally. The heat transfer coefficient and stagnation temperature at the efflux deflecting surface are calculated theoretically with the aid of model test results. Heat transfer coefficients derived from temperature measurements on steel plates embedded in the deflecting surface are compared with the theoretical results. It is concluded that simple aerodynamic heat transfer theory can provide an effective engineering estimate of the temperature rise of an efflux deflecting surface.

Bulk Temperature Development in Transient Heat Transfer Measurements Using Heater Foils

2002 ◽  
Vol 124 (5) ◽  
pp. 982-985 ◽  
Author(s):  
Jens von Wolfersdorf
Keyword(s):  
Heat Transfer ◽  
Transient Heat Transfer ◽  
Simplified Model ◽  
Temperature History ◽  
Bulk Temperature ◽  
Transfer Coefficients ◽  
Transfer Experiment ◽  
Heat Transfer Coefficients ◽  
Temperature Development ◽  
Heat Transfer Parameter

The time and space development of the fluid bulk temperature in a transient heat transfer experiment for internal channel cooling investigations using heater foils is addressed. An analytical solution for uniform heat transfer coefficients is derived which shows the effect of wall heating on the bulk temperature during a transient test run. A simplified model is proposed for characterizing the bulk temperature development by introducing an upstream heat transfer parameter. With this, analytical solutions for the local wall temperature history can be derived. The presented solution can be used for data reduction of transient tests of this kind.

scholarly journals STUDY OF DIFFERENCES BETWEEN REAL AND EFFECTIVE HEAT TRANSFER COEFFICIENTS TO PROVIDE CORRECT DATA ON TEMPERATURE FIELD CALCULATIONS AND COMPUTER SIMULATIONS DURING HARDENING OF STEEL

2018 ◽  
Vol 3 ◽  
pp. 42-51
Author(s):  
Nikolai Kobasko
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Heat Capacity ◽  
Liquid Media ◽  
Transfer Coefficients ◽  
Heat Transfer Coefficients ◽  
Effective Heat ◽  
Testing Liquid ◽  
Core Cooling ◽  
Capacity Method

The paper analyses contemporary methods and probes for testing liquid media used as a quenchant in heat treating industry. It is shown that lumped-heat-capacity method, often used for testing liquid media, produces big errors during transient nucleate boiling processes due to incorrect calculation condition caused by use effective heat transfer coefficient (HTC). The effective heat transfer coefficients (HTCs), utilized for this purpose, are almost seven times less as compared with real HTCs that results in incorrect calculation the value of Bi. Instead of lumped-heat -capacity method, a general cooling rate equation is proposed for HTC calculation. It is underlined that effective HTCs can be used only for approximate core cooling rate and core cooling time of steel parts calculations. For investigation cooling capacity of liquid quenchants, including initial heat flux densities, HTCs and critical heat flux densities, high developed technique of solving inverse problem should be used based on accurate experimental data generated by testing liquid media with the Liscic/Petrofer probe or other similar technique.

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