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.

Conjugate Heat Transfer in Air-to-Refrigerant Airfoil Heat Exchangers

2014 ◽  
Vol 136 (8) ◽  
Author(s):  
Yutaka Ito ◽  
Naoya Inokura ◽  
Takao Nagasaki
Keyword(s):  
Heat Transfer ◽  
Carbon Dioxide ◽  
Heat Exchangers ◽  
Transfer Coefficients ◽  
Exchange System ◽  
Heat Transfer Coefficients ◽  
Nusselt Numbers ◽  
Heat Exchange System ◽  
Inverse Heat Transfer ◽  
Transfer Method

A light and compact heat exchange system was realized using two air-to-refrigerant airfoil heat exchangers and a recirculated heat transport refrigerant. Its heat transfer performance was experimentally investigated. Carbon dioxide or water was used as a refrigerant up to a pressure of 30 MPa. Heat transfer coefficients on the outer air-contact and inner refrigerant-contact surfaces were calculated using an inverse heat transfer method. Correlations were developed for the Nusselt numbers of carbon dioxide and water on the inner refrigerant-contact surface. Furthermore, we proposed a method to evaluate a correction factor corresponding to the thermal resistance of the airfoil heat exchanger.

3-D Inverse Heat Transfer in a Composite Target Subject to High-Energy Laser Irradiation

2011 ◽  
Author(s):  
Jianhua Zhou ◽  
Yuwen Zhang ◽  
J. K. Chen ◽  
Z. C. Feng
Keyword(s):  
Heat Transfer ◽  
Gas Flow ◽  
Heat Conduction Problem ◽  
High Energy ◽  
Inverse Heat Conduction Problem ◽  
Back Surface ◽  
Composite Target ◽  
Inverse Heat Transfer ◽  
Energy Laser ◽  
High Energy Laser

A new numerical model is developed to simulate the 3-D inverse heat transfer in a composite target with pyrolysis and outgassing effects. The gas flow channel size and gas addition velocity are determined by the rate equation of decomposition chemical reaction. The thermophysical properties of the composite considered are temperature-dependent. A nonlinear conjugate gradient method (CGM) is applied to solve the inverse heat conduction problem for high-energy laser-irradiated composite targets. It is shown that the front-surface temperature can be recovered with satisfactory accuracy based on the temperature/heat flux measurements on the back surface and the temperature measurement at an interior plane.

Determination of Non-Uniform Heat Transfer Coefficients Around a Solid Aluminum Alloy Complex Shape During Quenching by Using an Inverse Method

2002 ◽  
Author(s):  
Pen-Chung Chen ◽  
Deborah A. Kaminski ◽  
Robert W. Messler
Keyword(s):  
Heat Transfer ◽  
Gas Turbine ◽  
Inverse Method ◽  
Flux Measurement ◽  
Transient Temperature ◽  
Transfer Coefficients ◽  
Heat Transfer Coefficients ◽  
Uniform Heat ◽  
The Cost ◽  
Transfer Problems

Gas turbine systems include complex heat transfer problems. Especially, the cooling efficiency is critical to the operation of gas turbine. In order to achieve the desired cooling condition, one needs to know the distribution of heat transfer on the components; however, the cost to implement a full-scale gas turbine test is tremendous. Therefore, many researchers used simplified models to acquire the test data; certain experiments can provide heat flux measurement, whereas other techniques can measure heat transfer coefficients. The direct measurement of heat transfer coefficients on the surface of components is extremely difficult. In such situations, the inverse method using transient temperature measurements taken within the part can be used to determine heat transfer coefficients. By combining experiments and numerical modeling, this presentation attempts to provide an effective and robust method to determine heat transfer coefficients on the part’s surface during cooling. Though the setting of the present paper is the quenching of a part, the technique presented is proposed for in-service heat load. To characterize the present situation, i.e., non-uniform heat transfer coefficients occurring during quenching, a unique methodology for employing inverse heat conduction was developed to obtain heat transfer coefficients from temperature responses. In conventional inverse approaches, the heat transfer coefficient is assumed to be uniform around the periphery, but this approach sometimes is unrealistic, especially for complex shaped parts. In this study, experimental data were used to find parameters in a heat transfer correlation, rather than to determine the coefficients directly. The resulting analysis provided an improved fit to measurements compared to conventional inverse approaches. The method developed was robust and is extendable to parts of arbitrary shape.

Investigation of Transient Heat Transfer Coefficients in Quenching Experiments

1990 ◽  
Vol 112 (4) ◽  
pp. 843-848 ◽  
Author(s):  
A. M. Osman ◽  
J. V. Beck
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Temperature Response ◽  
Transient Heat Transfer ◽  
Transient Temperature ◽  
Empirical Correlations ◽  
Transfer Coefficients ◽  
Heat Transfer Coefficients ◽  
Inverse Heat Transfer

Methodological and experimental aspects of the estimation of transient heat transfer coefficients in quenching experiments, using inverse heat transfer methods, were addressed and investigated. Beck’s method was used for the estimation of the transient heat transfer coefficient history from interior transient temperature measurements during quenching. Experiments involved plunging a high-purity copper sphere into cooling baths without boiling. The sphere was instrumented with several interior thermocouples for measuring the transient temperature response during quenching. Water and ethylene glycol were investigated. The early transient values of the heat transfer coefficient history were found to be about 100–120 percent higher than the values predicted using well-known empirical correlations for free convection. The later time values were in good agreement with those predicted with empirical correlations. The transient inverse technique has the capability of estimating early transients and subsequent quasi-steady-state values of heat transfer coefficient in a single transient experiment.

Analysis of the Heat Transfer Coefficients on the Top of a Marine Diesel Piston Using the Inverse Heat Conduction Method

2011 ◽  
Vol 291-294 ◽  
pp. 1657-1661 ◽  
Author(s):  
Tao He ◽  
Xi Qun Lu ◽  
Yi Bin Guo
Keyword(s):  
Heat Transfer ◽  
Heat Conduction ◽  
Optimization Problem ◽  
Heat Conduction Problem ◽  
Inverse Heat Conduction Problem ◽  
Measured Temperature ◽  
Inverse Heat Conduction ◽  
Transfer Coefficients ◽  
Conduction Model ◽  
Marine Diesel

An efficient method utilizing the concept of inverse heat conduction is presented for the thermal analysis of pistons based on application to the piston head of a marine diesel engine. An inverse heat conduction problem is established in the form of an optimization problem. In the optimization problem, the convection heat transfer coefficient（HTC）on the top side of the piston is defined as the design variable, while the error between the measured and analysed temperatures is defined as objective function. For the optimization, an axi-symmetrical finite element conduction model is presented. The optimum distribution of the HTC at the top side of piston is successfully determined through a numerical implementation. The temperature obtained via an analysis using the optimum HTC is compared with the measured temperature, and reasonable agreement is obtained. The present method can be effectively utilized to analyze the temperature distribution of engine pistons.

Heat Transfer and Pressure Drop Measurements for a Square Channel With 45 deg Round-Edged Ribs at High Reynolds Numbers

2010 ◽  
Vol 133 (3) ◽  
Author(s):  
Akhilesh P. Rallabandi ◽  
Nawaf Alkhamis ◽  
Je-Chin Han
Keyword(s):  
Heat Transfer ◽  
Friction Factor ◽  
Reynolds Numbers ◽  
Transfer Coefficients ◽  
Height Ratio ◽  
Square Channel ◽  
Heat Transfer Coefficients ◽  
Friction Factors ◽  
High Reynolds ◽  
The Cost

Experiments to determine heat transfer coefficients and friction factors are conducted on a stationary 45 deg parallel rib-roughened square channel, which simulates a turbine blade internal coolant passage. Copper plates fitted with silicone heaters and thermocouples are used to measure regionally averaged heat transfer coefficients. Reynolds numbers studied range from 30,000 to 400,000. The ribs studied have rounded (filleted) edges to account for manufacturing limitations of actual engine blades. The rib height (e) to hydraulic diameter (D) ratio (e/D) ranges from 0.1 to 0.2, while spacing (p) to height ratio (p/e) ranges from 5 to 10. Results indicate an increase in the heat transfer due to the ribs at the cost of a higher friction factor, especially at higher Reynolds numbers. Round-edged ribs experience a similar heat transfer coefficient and a lower friction factor compared with sharp-edged ribs, especially at higher values of the rib height. Correlations predicting Nu and f as a function of e/D, p/e, and Re are presented. Also presented are correlations for the heat transfer and friction roughness parameters (G and R, respectively).

Numerical Analysis of Heat Conduction in Cooling of Aluminum Extrusion

2002 ◽  
Author(s):  
Nicola Bianco ◽  
Oronzio Manca
Keyword(s):  
Heat Transfer ◽  
Heat Conduction ◽  
Cooling System ◽  
Heat Conduction Problem ◽  
Aluminum Extrusion ◽  
Transfer Coefficients ◽  
Lower Velocity ◽  
Heat Transfer Coefficients ◽  
Water Sprays ◽  
Volume Method

A thermal analysis of the cooling of an extruded aluminum alloy by means of water sprays is carried out. The heat conduction problem has been solved numerically by means of a finite volume method. The heat transfer coefficients used in the boundary conditions has been evaluated by means of spray heat transfer correlations, which relate these coefficients to the spray hydrodynamic parameters. The influence of the number of sprays and of the solid velocity has been investigated. Results show that the efficiency of the cooling system decreases as the number of jets increases. The efficiency of each spray increases with the velocity for the same number of sprays. As the workpiece velocity increases it needs to increase the number of sprays to obtain the same temperature difference between the entry and the exit of the cooling system. The greater the number of sprays related to the case with lower velocity, the smaller the increase of the number of sprays.

scholarly journals Database for Research Projects to Solve the Inverse Heat Conduction Problem

Data ◽  
2019 ◽  
Vol 4 (3) ◽  
pp. 90
Author(s):  
Sándor Szénási ◽  
Imre Felde
Keyword(s):  
Heat Transfer ◽  
Machine Learning ◽  
Transfer Problem ◽  
Heat Conduction Problem ◽  
Inverse Heat Conduction Problem ◽  
Training Data ◽  
Work Piece ◽  
Heuristic Search Algorithms ◽  
Inverse Heat Transfer ◽  
Inverse Heat Transfer Problem

To achieve the optimal performance of an object to be heat treated, it is necessary to know the value of the Heat Transfer Coefficient (HTC) describing the amount of heat exchange between the work piece and the cooling medium. The prediction of the HTC is a typical Inverse Heat Transfer Problem (IHCP), which cannot be solved by direct numerical methods. Numerous techniques are used to solve the IHCP based on heuristic search algorithms having very high computational demand. As another approach, it would be possible to use machine-learning methods for the same purpose, which are capable of giving prompt estimations about the main characteristics of the HTC function. As known, a key requirement for all successful machine-learning projects is the availability of high quality training data. In this case, the amount of real-world measurements is far from satisfactory because of the high cost of these tests. As an alternative, it is possible to generate the necessary databases using simulations. This paper presents a novel model for random HTC function generation based on control points and additional parameters defining the shape of curve segments. As an additional step, a GPU accelerated finite-element method was used to simulate the cooling process resulting in the required temporary data records. These datasets make it possible for researchers to develop and test their IHCP solver algorithms.

Note. End-over-end agitation processing of cans containing liquid particle mixtures. Influence of continuous versus oscillatory rotation / Nota. Agitación por volteo de latas con una mezcla de líquido y partículas en suspensión. Influencia de la agitación en continuo y oscilatoria

1999 ◽  
Vol 5 (5) ◽  
pp. 385-389 ◽  
Author(s):  
S.S. Sablani ◽  
H.S. Ramaswamy
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Water Immersion ◽  
Pilot Scale ◽  
Transfer Coefficients ◽  
Heat Transfer Coefficients ◽  
Inverse Heat Transfer ◽  
Continuous Rotation ◽  
Effects Of Rotation

Convective heat transfer coefficients were evaluated during end-over-end rotation processing of cans filled with liquid and particle mixtures in a pilot-scale, overpressure water-immersion, rotary retort. Two modes of end-over-end agitation were employed, one involving a continuous and the other involving an oscillatory rotation of the cage containing cans. Nylon spheres of diameter 0.025 m were used as test particles and a high temperature bath oil was used as the test liquid. A lumped capacity approach was employed to determine the overall heat transfer coefficient, U, and an inverse heat transfer approach was used to determined the fluid to particle heat transfer coefficient, hfp. Effects of the two modes of rotation (continuous and oscillation) on the associated heat transfer coefficients were evaluated at three speeds (8, 16 and 24 rpm) and three radii of rotation (0,13 and 26 cm). An analysis of variance showed that the effects of rotation speed and mode of rotation on both U and htp were significant ( p < 0.05). However, the effect of radius of rotation was significant only with U. These factors also affected the calculated process times for achieving an accumulated lethality ( Fo) of 10 min at the particle center and in the can liquid in a similar fashion. In general, U and hfp values associated with continuous rotation were 10-40% higher than those associated with oscillatory rotation.

scholarly journals Heat Transfer Coefficient Identification in Mini-Channel Flow Boiling with the Hybrid Picard–Trefftz Method

Energies ◽  
2018 ◽  
Vol 11 (8) ◽  
pp. 2057 ◽  
Author(s):  
Mirosław Grabowski ◽  
Sylwia Hożejowska ◽  
Anna Pawińska ◽  
Mieczysław Poniewski ◽  
Jacek Wernik
Keyword(s):  
Heat Transfer ◽  
Test Section ◽  
Two Phase Flow ◽  
Heat Conduction Problem ◽  
Flow Boiling ◽  
Inverse Heat Conduction Problem ◽  
Phase Flow ◽  
Transfer Coefficients ◽  
Two Phase ◽  
Trefftz Method

This paper summarizes the results of the flow boiling heat transfer study with ethanol in a 1.8 mm deep and 2.0 mm wide horizontal, asymmetrically heated, rectangular mini-channel. The test section with the mini-channel was the main part of the experimental stand. One side of the mini-channel was closed with a transparent sight window allowing for the observation of two-phase flow structures with the use of a fast film camera. The other side of the channel was the foil insulated heater. The infrared camera recorded the 2D temperature distribution of the foil. The 2D temperature distributions in the elements of the test section with two-phase flow boiling were determined using (1) the Trefftz method and (2) the hybrid Picard–Trefftz method. These methods solved the triple inverse heat conduction problem in three consecutive elements of the test section, each with different physical properties. The values of the local heat transfer coefficients calculated on the basis of the Robin boundary condition were compared with the coefficients determined with the simplified approach, where the arrangement of elements in the test section was treated as a system of planar layers.

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