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Spray angle effect during spray cooling of microelectronics: Experimental measurements and comparison with inverse calculations

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APPLIED THERMAL ENGINEERING 2006年第16期26卷 1788-1795页

作者： Li, B. Q. Cader, T. Schwarzkopf, J. Okamoto, K. Ramaprian, B. Washington State Univ Sch Mech & Mat Engn Pullman WA 99164 USA Isothermal Syst Res Liberty Lake WA 99019 USA

An experimental and inverse computational study is presented of spray cooling of microelectronics with an emphasis on the spray angle effects on cooling performance. A thermal test chip provides the heated target, and is cooled by a single pressure swirl atomizer. Thermal readings were taken at the spray angles of 0-60 degrees, at a fixed distance of 1.4 cm from the heated die surface. An inverse heat transfer computational algorithm is developed to calculate the unknown spray cooling heat fluxes using the measured temperature data inside the die. The computational scheme is a combination of the finite element method and the truncated single value decomposition with the discrepancy principle for determining the optimal truncation threshold value. Good agreement is obtained between the experimental measurements and calculated results. For this particular system, a direct estimate using temperature readings at two adjacent points would produce incorrect heat flux results and an inverse algorithm is deemed essential if an accurate heat flux is to be obtained from the measurements. It is found that a major cause for the drop-off is the reduction in spray volumetric flux delivered to the die at the greater spray angles. (c) 2006 Elsevier Ltd. All rights reserved.

关键词： spray cooling inverse algorithm the truncated singular value decomposition discrepancy principle spray angle effect

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inverse method for the determination of elastic properties of coating layers by the surface ultrasonic waves

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2005年第9期6卷 945-949页

作者：常军杨震许金泉 School of Naval Architecture Ocean and Civil Engineering Shanghai Jiaotong University Shanghai 200240 China

As the coated materials are widely applied in engineering, estimation of the elastic properties of coating layers is of great practical importance. This paper presents an inversion algorithm for determining the elastic properties of coating layers from the given velocity dispersion of surface ultrasonic waves. Based on the dispersive equation of surface waves in layered half space, an objective function dependent on coating material parameters is introduced. The density and wave velocities, which make the object function minimum, are taken as the inversion results. inverse analyses of two parameters (longitudinal and transverse velocities) and three parameters (the density, longitudinal and transverse velocities) of the coating layer were made.

关键词： Coating layers Surface waves Dispersive equation inverse algorithm

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NEW ADVANCES IN ELECTROMAGNETIC SCATTERING AND inverse SCATTERING FROM SUBSURFACE PROFILES

NEW ADVANCES IN ELECTROMAGNETIC SCATTERING AND INVERSE SCATT...

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IEEE International Geoscience and Remote Sensing Symposium (IGARSS)

作者： Wu, Chao Rao, Liting Cui, Shuai Wang, Youcheng Zhang, Xiaojuan Fang, Guangyou Chinese Acad Sci Inst Elect Beijing 100190 Peoples R China

ISBN: (纸本)9781479911141

We propose a new method for bistatic scattering from hybrid subsurface profiles with multilayer rough interfaces and flat boundaries, which the fast method is firstly demonstrated by strictly theoretical formulas in the framework of classical small perturbation method (SPM) without other else approximation and assumption strategy. What is more, we can obtain general compact closed-form first-order perturbation solutions of hybrid subsurface profiles with an arbitrary number of rough and smooth interfaces, which is necessary to insure a successful inversion process. We employ improved inverse algorithms and get successful inverse process based on the proposed forward model.

关键词： Bistatic scattering hybrid subsurface profiles inverse algorithm multilayer rough interfaces small perturbation method

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A Novel inverse Method for Automatic UAV Line Patrolling with Magnetic Sensors 60

A Novel Inverse Method for Automatic UAV Line Patrolling wit...

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Joint 60th IEEE International Symposium on Electromagnetic Compatibility (EMC) / IEEE Asia-Pacific Symposium on Electromagnetic Compatibility (APEMC)

作者： Gao, Feng Wang, Sen Wu, Yang Zhao, Gen Wang, Bo Hu, Jun Shaanxi Elect Power Res Inst 669 HangTianZhong Rd Xian Shaanxi Peoples R China Tsinghua Univ Dept Elect Engn State Key Lab Power Syst Beijing Peoples R China

ISBN: (纸本)9781509059973

As the trunk of the power system, defects of the overhead transmission lines may result in failure of power system operation. Therefore, line patrolling, which means inspection of the transmission lines should be carried out in a regular routine. This article proposes a novel automatic transmission line patrolling method using UAV and magnetic sensors. Geometric relationship and relative position models are proposed to inverse the location and current of the conductor via optimization algorithms. A simulation platform of three-phase AC transmission lines is established and the feasibility of the two models is verified. A parabola fitting method is exploited to simulate the line sag of the transmission system. The inverse result can be used to guide UAV's patrolling around the line. This method makes UAV autonomous patrolling possible, which brings about lower cost, higher efficiency and broad prospect.

关键词： overhead transmission line UAV magnetic sensor inverse algorithm parabola fitting

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Estimation of pollutant sources in multi-zone buildings through different deconvolution algorithms

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Building Simulation 2022年第5期15卷 817-830页

作者： Mo Li Fei Li Yuanqi Jing Kai Zhang Hao Cai Lufang Chen Xian Zhang Lihang Feng College of Urban Construction Nanjing Tech UniversityNanjing210009China Institute of Defense Engineering Academy of Military SciencePLABeijing100850China College of Electrical Engineering and Control Science Nanjing Tech UniversityNanjing210009Chino

Effective identification of pollution sources is particularly important for indoor air *** estimation of source strength is the basis for source effective *** paper proposes an optimization method for the deconvolution process in the source strength inverse *** the scheme,the concept of time resolution was defined,and combined with different filtering positions and filtering *** measures to reduce effects of measurement noise were quantitatively ***,the performances of nine deconvolution inverse algorithms under experimental and simulated conditions were evaluated and *** hybrid algorithms were proposed and compared with single algorithms including Tikhonov regularization and iterative *** showed that for the filtering position and algorithm,Butterworth filtering performed better,and different filtering positions had little effect on the inverse *** the calculation time step,the optimal Tr(time resolution)was 0.667%and 1.33%in the simulation and experiment,*** hybrid algorithms were found to not perform better than the single algorithms,and the SART(simultaneous algebraic reconstruction technique)algorithm from CAT(computer assisted tomography)yielded better performances in the accuracy and stability of source strength *** relative errors of the inverse calculation for source strength were typically below 25%using the optimization scheme.

关键词： pollutant source measurement noise inverse algorithm indoor air algorithm ranking

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Study on three-dimensional natural convection heat transfer in a house with two heating surfaces

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JOURNAL OF THERMAL ANALYSIS AND CALORIMETRY 2024年第22期149卷 13175-13197页

作者： Chen, Han-Taw Wang, Soft-Heart Rashidi, Saman Yan, Wei-Mon Natl Cheng Kung Univ Dept Mech Engn Tainan 701 Taiwan Semnan Univ Fac New Sci & Technol Dept Energy Semnan Iran Natl Taipei Univ Technol Dept Energy & Refrigerating Air Conditioning Engn Taipei 10608 Taiwan Natl Taipei Univ Technol Res Ctr Energy Conservat New Generat Residential Commercial & Ind Sect Taipei 10608 Taiwan

In order to explore the heat transfer properties of natural convection in the cavity, this article uses the three-dimensional CFD inverse method and the temperature measurement points based on the experimental results. In addition, different flow modes and mesh divisions are used. For the applicability of different turbulence models, the least squares method is then used to calculate Q value of the heat source in the cavity and compare that with the experimental measurement results and consistent with the overall trend. Finally, the temperature distribution diagram and velocity streamline diagram of the simulation results are provided to visualize the flow field and analyze its heat transfer characteristics. The results show that the flow pattern and the number of grid points have a great influence on the results. In terms of experiments, with the change of the cavity size and the influence of the opening, the air flow will be different. To achieve the effect of enhancing natural convection, due to the inflow of a large amount of cold air, although the overall temperature of the cavity is greatly reduced, the upper cold wall is surrounded by cold air, which reduces the heat transfer coefficient. In order to verify the reliability and usability of the results of the inverse algorithm in this article, the obtained results of heat transfer coefficient and heat dissipation are compared with previous results or empirical formulas in other related literature. When the height drops from h = 0.1 m to h = 0.05 m, the average increase in heat transfer coefficient is 2.79%;while for the height drops from h = 0.05 m to h = 0.02 m, the average increase in heat transfer coefficient is 74.8%. When side fin length is reduced form W2 = 0.1 m to W2 = 0.08 m, the average increase in heat transfer coefficient is 14.33%;when side fin length is reduced form W2 = 0.08 m to W2 = 0.06 m, the average increase in heat transfer coefficient is 41.28%.

关键词： inverse algorithm Computational fluid dynamics Closed cavity Natural convection Turbulence models Energy efficiency

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Determination of the heat transfer coefficient at the workpiece-die interface for the forging process

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PROCEEDINGS OF THE INSTITUTION OF MECHANICAL ENGINEERS PART B-JOURNAL OF ENGINEERING MANUFACTURE 2002年第8期216卷 1179-1186页

作者： Chang, CC Bramley, AN Univ Bath Dept Engn & Appl Sci Bath BA2 7AY Avon England

This paper describes an investigation of the determination of the heat transfer coefficient at the workpiece-die interface for the forging process. A surface thermocouple has been constructed to measure the temperature at the die surface, where a high pressure occurs, for the simple upsetting forging process. The process was also simulated by a commercial finite element package. The measured and predicted temperatures were then used in an inverse algorithm with an iterative approach to determine the interface heat transfer coefficient (IHTC). The results show that the predicted temperatures modelled by a constant IHTC at the rest-on-die stage were in good agreement with the experimental measurement. However, for the forging stage, the IHTC values vary significantly during the process. This has important consequences in the implementation of simulation software.

关键词： forging heat transfer coefficient inverse algorithm

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Analysis of non-uniform thermal behaviour of special steel during slab continuous casting

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IRONMAKING & STEELMAKING 2018年第4期45卷 350-355页

作者： Du, F. Wang, X. Han, X. Xu, J. Yao, M. Dalian Maritime Univ Coll Marine Engn Linghai Rd 1 Dalian 116024 Liaoning Peoples R China Dalian Univ Technol Sch Mat Sci & Engn Linggong Rd 2 Dalian 116024 Liaoning Peoples R China Dalian Maritime Univ Key Lab Ship Maintenance & Manufacture Linghai Rd 1 Dalian 116024 Liaoning Peoples R China

A full-scale finite-element model of a slab and its mould was developed to reveal the complex thermal behaviour of special steel in a vertical caster during slab continuous casting. An inverse algorithm was applied to calculate the heat flux and combined with the temperatures measured using thermocouples that were buried in different positions of the mould. The model was validated by comparing the calculated temperature with the measured ones. The temperature distribution of the slab is not symmetric, reflecting the non-uniform nature of heat transfer and hence the necessity of formulating a full-scale model. It will provide a helpful tool for further improving the casting parameters and operations for special steel.

关键词： Full-scale finite-element model inverse algorithm Special steel Continuous casting

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Three-dimensional radiative transfer tomography for turbid media

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IEEE JOURNAL OF SELECTED TOPICS IN QUANTUM ELECTRONICS 2003年第2期9卷 189-198页

作者： Cai, W Xu, M Alfano, RR CUNY City Coll Inst Ultrafast Spect & Lasers New York State Ctr Adv Technol Ultrafast Photon M Dept Phys New York NY 10031 USA CUNY Grad Sch New York State Ctr Adv Technol Ultrafast Photon M Inst Ultrafast Spect & LasersDept Phys New York NY 10031 USA

The photon distribution, as a function of position, angle, and time, is computed using the analytical cumulant solution of the Boltzmann radiative transfer equation (RTE). A linear forward model for light propagation in turbid media for three-dimensional (3-D) optical tomography is formed based on this solution. The model can be used with time resolved, continuous wave (CW), and frequency-domain measurements in parallel geometries. This cumulant forward model (CFM) is more accurate than that based on the diffusion approximation of RTE. An inverse algorithm that incorporates this CFM is developed, based on a fast 3-D hybriddual-Fourier tomographic approach using multiple detectors and multiple sources in parallel geometries. The inverse algorithm can produce a 3-D image of a turbid medium with more than 20 000 voxels in 1-2 min using a personal. computer. A 3-D image reconstructed from simulated data is, presented.

关键词： absorption and scattering forward model inverse algorithm optical tomography photon migration radiative transfer equation (RTE)

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Concurrent Identification of Impact Location and Force Magnitude on a Composite Panel

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INTERNATIONAL JOURNAL OF STRUCTURAL STABILITY AND DYNAMICS 2020年第10期20卷

作者： Kalhori, Hamed Alamdari, Mehrisadat Makki Li, Bing Halkon, Ben Hosseini, Seyedeh Marzieh Ye, Lin Li, Zheng Univ Technol Sydney Sch Mech & Mechatron Engn Ultimo NSW 2007 Australia Bu Ali Sina Univ Fac Engn Dept Mech Engn Hamadan Hamadan Iran Univ New South Wales Sch Civil & Environm Engn Sydney NSW 2052 Australia Northwestern Polytech Univ Sch Aeronaut Xian 710072 Shaanxi Peoples R China Univ Sydney Sch Aerosp Mech & Mechatron Engn Sydney NSW 2006 Australia Peking Univ Coll Engn Dept Mech & Aerosp Engn Beijing 100871 Peoples R China

Simultaneous estimation of both the location and force history of an impact applied on a lattice truss core sandwich panel is inversely carried out utilizing velocity signals collected by means of a scanning laser Doppler vibrometer. The algorithm assumes that several impact forces are exerted concurrently on a number of specified locations on a panel, provided that the magnitude of all impact forces but one is actually equal to zero. This condition equates to a scenario where an impact occurs at only one location. The purpose is therefore to detect the actual impact location among all potential locations, together with its force history, through minimizing error functions. Two algorithms, the one-to-one (even-determined) approach and the superposition approach, are considered. The one-to-one approach solves the reconstruction problem independently for each pair of impact and measurement points. However, in the superposition approach, the impact forces at all potential locations are concurrently reconstructed through a single matrix equation. It is shown that the one-to-one approach fails to detect the true impact location while the superposition approach recognizes the actual impact location based on some qualitative evaluating criteria. Adopting the superposition approach, for a problem with four possible impact locations, two scenarios one with four and one with 12 measurement points, are investigated. It is observed that the additional measurement points do not necessarily enhance the efficiency and accuracy of the proposed method. It is found that different arrangements of measuring points lead to identification of the location and the magnitude of the impact force, though the use of four evenly distributed measurement points seems to be most effective in simultaneous identification of the location and magnitude of the impact force. Further, a quantitative index based on the concept of similarity search for time-series using wavelet transformation is proposed a

关键词： Composite impact force identification inverse algorithm similarity searching wavelet transform

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