Thermal Responses of a Thin Plate under Periodic Heat Flux Oscillation

2014 ◽  
Vol 578-579 ◽  
pp. 902-906
Author(s):  
Qiang Nian Li
Keyword(s):  
Heat Flux ◽  
Heat Conduction ◽  
Thin Plate ◽  
Separation Of Variables ◽  
Temperature Response ◽  
Conservation Equation ◽  
Conduction Model ◽  
Thermal Behaviors ◽  
Heat Flux Vector ◽  
Periodic Heat

Thermal behaviors of a thin plate under a periodic surface thermal disturbance are investigated. The temperature and the displacement responses are predicted using the parabolic heat conduction model. The solution of temperature response is obtained by separation of variables. Firstly, an analytic expression of heat flux filed within the plate is obtained by using the parabolic heat conduction equation which is described by heat flux vector, then, based on the conservation equation of energy, the temperature response is given. The displacement response of the plate is solved analytically using the Nowachi’s and the Navier’s approachs. The thermal behaviors of a plate with various relatively parameters is calculated numerically and the results shown graphically.

A Comparison of Radiation Versus Convection Calibration of Thin-Film Heat Flux Gauges

1999 ◽  
Author(s):  
D. E. Smith ◽  
J. V. Bubb ◽  
O. Popp ◽  
T. E. Diller ◽  
Stephen J. Hevey
Keyword(s):  
Thin Film ◽  
Heat Flux ◽  
Surface Temperature ◽  
Temperature Response ◽  
Turbine Rotor ◽  
Separate Experiment ◽  
Measured Temperature ◽  
Conduction Model ◽  
Time Resolved ◽  
Turbine Rotor Blade

Abstract A transient, in-situ method was examined for calibrating thin-film heat flux gauges using experimental data generated from both convection and radiation tests. Also, a comparison is made between this transient method and the standard radiation substitution calibration technique. Six Vatell Corporation HFM-7 type heat flux gauges were mounted on the surface of a 2-D, first-stage turbine rotor blade. These gauges were subjected to radiation from a heat lamp and in a separate experiment to a convective heat flux generated by flow in a transonic cascade wind tunnel. A second set of convective tests were performed using jets of cooled air impinging on the surface of the gauges. Direct measurements were simultaneously taken of both the time-resolved heat flux and surface temperature on the blade. The heat flux input was used to predict a surface temperature response using a one-dimensional, semi-infinite conduction model into a substrate with known thermal properties. The sensitivities of the gauges were determined by correlating the semi-infinite predicted temperature response to the measured temperature response. A finite-difference code was used to model the penetration of the heat flux into the substrate in order to estimate the time for which the semi-infinite assumption was valid. The results from these tests showed that the gauges accurately record both the convection and radiation modes of heat transfer. The radiation and convection tests yielded gauge sensitivities which agreed to within ±11%.

scholarly journals Non-Fourier Heat Conduction of a Functionally Graded Cylinder Containing a Cylindrical Crack

2020 ◽  
Vol 2020 ◽  
pp. 1-11 ◽  
Author(s):  
Jiawei Fu ◽  
Keqiang Hu ◽  
Linfang Qian ◽  
Zengtao Chen
Keyword(s):  
Heat Flux ◽  
Heat Conduction ◽  
Intensity Factor ◽  
Functionally Graded ◽  
Conduction Model ◽  
Heat Conduction Model ◽  
Flux Intensity ◽  
Cylindrical Crack ◽  
Heat Flux Intensity ◽  
Fourier Heat Conduction

The present work investigates the problem of a cylindrical crack in a functionally graded cylinder under thermal impact by using the non-Fourier heat conduction model. The theoretical derivation is performed by methods of Fourier integral transform, Laplace transform, and Cauchy singular integral equation. The concept of heat flux intensity factor is introduced to investigate the heat concentration degree around the crack tip quantitatively. The temperature field and the heat flux intensity factor in the time domain are obtained by transforming the corresponding quantities from the Laplace domain numerically. The effects of heat conduction model, functionally graded parameter, and thermal resistance of crack on the temperature distribution and heat flux intensity factor are studied. This work is beneficial for the thermal design of functionally graded cylinder containing a cylindrical crack.

Effect of Brownian and Thermophoretic Diffusions of Nanoparticles on Nonequilibrium Heat Conduction in Nanofluids

2008 ◽  
Author(s):  
Yuwen Zhang ◽  
Ling Li ◽  
H. B. Ma
Keyword(s):  
Heat Flux ◽  
Heat Conduction ◽  
Initial Temperature ◽  
Volume Fraction ◽  
Density Ratio ◽  
Lewis Number ◽  
Soret Coefficient ◽  
Transfer Enhancement ◽  
Initial Volume Fraction ◽  
Periodic Heat

Effects of Brownian and thermophoretic diffusions on nonequilibrium heat conduction in a nanofluid layer with periodic heat flux on one side and specified temperature on the other side are investigated numerically. The problem are described by eight dimensionless parameters: density ratio, heat capacity ratio, Lewis number, Soret coefficient, initial volume fraction of nanoparticles, initial temperature, Sparrow number, and period of the surface heat flux. Effects of Brownian and thermophoretic diffusions of nanoparticles on nonequilibrium heat conduction in nanofluid obtained by dispersing copper nanoparticles into ethylene glycol are investigated. The results showed that the Brownian and thermophoretic diffusions only affect the nanoparticle temperature but their effect on the heat transfer enhancement is negligible.

Generalized Solution for Two-Dimensional Transient Heat Conduction Problems With Partial Heating Near a Corner

2019 ◽  
Vol 141 (7) ◽  
Author(s):  
Robert L. McMasters ◽  
Filippo de Monte ◽  
James V. Beck
Keyword(s):  
Boundary Condition ◽  
Heat Flux ◽  
Heat Conduction ◽  
Steady State ◽  
Separation Of Variables ◽  
Transient Heat Conduction ◽  
Generalized Solution ◽  
Convective Heating ◽  
Two Dimensional ◽  
Partial Heating

A generalized solution for a two-dimensional (2D) transient heat conduction problem with a partial-heating boundary condition in rectangular coordinates is developed. The solution accommodates three kinds of boundary conditions: prescribed temperature, prescribed heat flux and convective. Also, the possibility of combining prescribed heat flux and convective heating/cooling on the same boundary is addressed. The means of dealing with these conditions involves adjusting the convection coefficient. Large convective coefficients such as 1010 effectively produce a prescribed-temperature boundary condition and small ones such as 10−10 produce an insulated boundary condition. This paper also presents three different methods to develop the computationally difficult steady-state component of the solution, as separation of variables (SOV) can be less efficient at the heated surface and another method (non-SOV) is more efficient there. Then, the use of the complementary transient part of the solution at early times is presented as a unique way to compute the steady-state solution. The solution method builds upon previous work done in generating analytical solutions in 2D problems with partial heating. But the generalized solution proposed here contains the possibility of hundreds or even thousands of individual solutions. An indexed numbering system is used in order to highlight these individual solutions. Heating along a variable length on the nonhomogeneous boundary is featured as part of the geometry and examples of the solution output are included in the results.

Modeling of Temperature Distributions in the Workpiece During Abrasive Waterjet Machining

1993 ◽  
Vol 115 (2) ◽  
pp. 446-452 ◽  
Author(s):  
M. M. Ohadi ◽  
K. L. Cheng
Keyword(s):  
Heat Flux ◽  
Heat Conduction ◽  
Abrasive Waterjet ◽  
Block Type ◽  
Analysis Tool ◽  
Operational Parameters ◽  
Conduction Model ◽  
Steady State Condition ◽  
Temperature Distributions ◽  
Awj Cutting

Modeling of temperature distributions in a block-type workpiece during cutting with an abrasive waterjet (AWJ) was the subject of an analytical/experimental investigation in the present study. The experiments included measurement of detailed time-temperature distributions in the workpiece for selected AWJ/workpiece operational parameters. Mathematical modeling of the problem made use of a two-part process. In the first part, the measured experimental data were fed into an inverse heat conduction algorithm, which determined the corresponding heat flux in the workpiece. In the second part, this heat flux was fed into a two-dimensional transient heat conduction model that calculated the corresponding temperature distributions in the workpiece. It is demonstrated that the proposed model can serve as a useful thermal analysis tool for AWJ cutting processes so long as a quasi-steady-state condition can be established in the workpiece.

On the Analysis of Short-Pulse Laser Heating of Metals Using the Dual Phase Lag Heat Conduction Model

2009 ◽  
Vol 131 (11) ◽  
Author(s):  
K. Ramadan ◽  
W. R. Tyfour ◽  
M. A. Al-Nimr
Keyword(s):  
Heat Flux ◽  
Heat Conduction ◽  
Laser Heating ◽  
Flux Distribution ◽  
Heat Losses ◽  
Phase Lag ◽  
Dual Phase ◽  
Heat Flux Distribution ◽  
Conduction Model ◽  
Initial Heat

Transient heat conduction in a thin metal film exposed to short-pulse laser heating is studied using the dual phase lag heat conduction model. The initial heat flux distribution in the film, resulting from the temporal distribution function of the laser pulse, together with the zero temperature gradients at the boundaries normally used in literature with the presumption that they are equivalent to negligible boundary heat losses is analyzed in detail in this paper. The analysis presented here shows that using zero temperature gradients at the boundaries within the framework of the dual phase lag heat conduction model does not guarantee negligible boundary heat losses unless the initial heat flux distribution is negligibly small. Depending on the value of the initial heat flux distribution, the presumed negligible heat losses from the boundaries can be even way larger than the heat flux at any location within the film during the picosecond laser heating process. Predictions of the reflectivity change of thin gold films due to a laser short heat pulse using the dual phase lag model with constant phase lags are found to deviate considerably from the experimental data. The dual phase lag model is found to overestimate the transient temperature in the thermalization stage of the laser heating process of metal films, although it is still superior to the parabolic and hyperbolic one-step models.

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