An analytical model for the prediction of temperature distribution and evolution in hybrid laser-waterjet micro-machining

2017 ◽  
Vol 47 ◽  
pp. 33-45 ◽  
Author(s):  
Shaochuan Feng ◽  
Chuanzhen Huang ◽  
Jun Wang ◽  
Hongtao Zhu ◽  
Peng Yao ◽  
...  
Keyword(s):  
Temperature Distribution ◽  
Analytical Model ◽  
Micro Machining

Analysis of Heat Transfer in Particle Velocity Sensor with Three-Wire Configuration

2020 ◽  
Author(s):  
Zhu Linhui ◽  
Shen Jienan ◽  
Zeng Yibo ◽  
Guo Hang
Keyword(s):  
Heat Transfer ◽  
Temperature Distribution ◽  
Forced Convection ◽  
Analytical Model ◽  
Particle Velocity ◽  
Structure Design ◽  
Distribution Model ◽  
Thermal Perturbation ◽  
Velocity Sensor ◽  
Perturbation Field

Abstract Particle velocity sensor (PVS) plays an important role in determining the type and location of a sound source. In this presentation, analytical model of heat transfer in PVS with a three-wire (SHS) configuration was first presented. By comparing with the thermal diffusion motion, the forced convection exerts a smaller influence on the temperature distribution. Thus, variation in forced convection could induce the formation of a thermal perturbation field. The overall temperature distribution model of a PVS is made up of a steady temperature field and a thermal perturbation field. With the derived model, PVS with SHS configuration has smaller thermal noise and higher signal-to-noise ratio in comparision with a two-wire (SS) configuration under the same conditions. Optimized parameters of structure design and heating power could be obtained via the analysis model. Also, this model gives optimal output performance and frequency-dependent characteristic curve. Numerical results are found to be in good agreement with the analytical solutions and experimental data, which verify the correctness of analytical model and numerical method. The study provides a basis for a theoretical and numerical analysis.

Analytical Model of the Soil Temperature Distribution Based on Weather Data

2020 ◽  
Author(s):  
M. Naser Reda ◽  
Markus Spinnler ◽  
Rajib Mahamud ◽  
Thomas Sattelmayer
Keyword(s):  
Temperature Distribution ◽  
Soil Temperature ◽  
Analytical Model ◽  
Numerical Models ◽  
Computational Cost ◽  
Weather Conditions ◽  
Solar Irradiation ◽  
Weather Data ◽  
Data Sets ◽  
Temperature Profiles

Abstract The measurement of soil temperature profiles for different locations or climates is essential for calculating the thermal performance of applications connected with the soil, e.g., underground heat storage systems. Estimating soil temperature profiles is identified as crucial knowledge for plant and crop growth as well as for germination in all agricultural tasks. The ground temperature depends on weather conditions (ambient temperature, solar irradiation, wind velocity, sky radiation, etc.) that contribute to the resulting temperature distribution within the soil close to the surface. In literature, several approaches have been discussed to predict soil temperature in different climates and locations, such as data-driven models, wavelet transform artificial neural networks, statistical models, etc. However, these models require extensive data sets from literature and high computational efforts. In the present study, a one-dimensional analytical model will be presented, which is based on the Green’s Function (GF) method. The model can estimate the daily and annual variation of the soil temperature distribution at different depths from real-time weather data sets. The model was experimentally validated with an accuracy of more than 96%. The significant advantage of the presented analytical method is the low computational cost, which is lower than that of numerical models by approximately two orders of magnitude.

An Analytical Model for Determining the Shear Angle in 1D Vibration-Assisted Micro Machining

2019 ◽  
Vol 2 (4) ◽  
pp. 199-214 ◽  
Author(s):  
Shamsul Arefin ◽  
XinQuan Zhang ◽  
Senthil Kumar Anantharajan ◽  
Kui Liu ◽  
Dennis Wee Keong Neo
Keyword(s):  
Analytical Model ◽  
Shear Angle ◽  
Micro Machining

Temperature Distribution in a Hollow Cylindrical Workpiece During Machining: Theoretical Model and Experimental Results

1991 ◽  
Vol 113 (4) ◽  
pp. 373-380 ◽  
Author(s):  
G. Subramani ◽  
M. C. Whitmore ◽  
S. G. Kapoor ◽  
R. E. DeVor
Keyword(s):  
Temperature Field ◽  
Temperature Distribution ◽  
Heat Source ◽  
Analytical Model ◽  
Initial Conditions ◽  
Temperature Response ◽  
Test Facility ◽  
Measured Temperature ◽  
Cylindrical Workpiece ◽  
Cylinder Bore

In this paper, an analytical model is developed for computation of the temperature distribution in a hollow cylindrical workpiece during machining with a single point tool. Such a model is useful for prediction of machined surface error arising from thermal expansion of the workpiece during machining. The model considers the interface between the tool and the workpiece to be a helically moving volumetric heat source. The governing equation satisfied by the temperature field, along with the appropriate boundary and initial conditions, is solved using the method of integral transforms. The experimental test facility used for the conduct of experiments for measurement of the temperature response in a cylindrical workpiece, namely a cylinder bore, during machining is discussed. The results from tests conducted using a laser as a heat source to verify the analytical model for temperature field are then presented. Several cylinder boring tests have been conducted, and the results from these tests along with the analysis performed with the temperature data to calibrate the temperature model are then discussed. Comparisons between predicted and measured temperature response in a cylinder bore during machining show good agreement.

Two-dimensional steady-state thermal analytical model of permanent-magnet synchronous machines operating in generator mode

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Zakarya Djelloul Khedda ◽  
Kamel Boughrara ◽  
Frédéric Dubas ◽  
Baocheng Guo ◽  
El Hadj Ailam
Keyword(s):  
Steady State ◽  
Temperature Distribution ◽  
Permanent Magnet ◽  
Analytical Model ◽  
Electrical Machines ◽  
Synchronous Machines ◽  
Analytical Prediction ◽  
Two Dimensional ◽  
Content Type ◽  
Proposed Model

Purpose Thermal analysis of electrical machines is usually performed by using numerical methods or lumped parameter thermal networks depending on the desired accuracy. The analytical prediction of temperature distribution based on the formal resolution of thermal partial differential equations (PDEs) by the harmonic modeling technique (or the Fourier method) is uncommon in electrical machines. Therefore, this paper aims to present a two-dimensional (2D) analytical model of steady-state temperature distribution for permanent-magnet (PM) synchronous machines (PMSM) operating in generator mode. Design/methodology/approach The proposed model is based on the multi-layer models with the convolution theorem (i.e. Cauchy’s product theorem) by using complex Fourier’s series and the separation of variables method. This technique takes into the different thermal conductivities of the machine parts. The heat sources are determined by calculating the different power losses in the PMSM with the finite-element method (FEM). Findings To validate the proposed analytical model, the analytical results are compared with those obtained by thermal FEM. The comparisons show good results of the proposed model. Originality/value A new 2D analytical model based on the PDE in steady-state for full prediction of temperature distribution in the PMSM takes into account the heat transfer by conduction, convection and radiation.

Flow and Heat Transfer Analysis of an Electro-Osmotic Flow Micropump for Chip Cooling

2014 ◽  
Vol 136 (3) ◽  
Author(s):  
K. Pramod ◽  
A. K. Sen
Keyword(s):  
Heat Transfer ◽  
Temperature Distribution ◽  
Analytical Model ◽  
Flow Rate ◽  
Maximum Flow ◽  
Back Pressure ◽  
Design Parameters ◽  
Chip Cooling ◽  
Flow And Heat Transfer ◽  
Electro Osmotic Flow

This paper reports theoretical and numerical analysis of fluid flow and heat transfer in a cascade electro-osmotic flow (EOF) micropump for chip cooling. A simple analytical model is developed to determine the temperature distribution in a two-dimensional (2D) single channel EOF micropump with forced convection due to a voltage difference between both ends. Numerical simulations are performed to determine the temperature distribution in the domain which is compared with that predicted by the model. A novel cascade EOF micropump with multiple microchannels in series and parallel and with an array of interdigitated electrodes along the flow direction is proposed. The simulations predict the maximum flow rate and pressure capability of one single stage of the micropump and the analytical model employs equivalent circuit theory to predict the total flow rate and back pressure. Each stage of the proposed micropump comprises sump and pump regions having opposing electric field directions. The various design parameters of the micropump includes the height of the pump and sump (h), number of stages (n), channel width (w), thickness of the channel wall or fin (r), and width ratio of the pump and sump (s:p) regions. Numerical simulations are performed to predict the effects of these design parameters on the pump performance which is compared with that predicted by the analytical model. The micropump is used for cooling cooling of an Intel® CoreTM i5 chip which produces a maximum heat of 95 W over an area of 3.75 × 3.75 cm. Based on the parametric studies a design for the cascade EOF micropump is proposed which provides a maximum flow rate of 14.16 ml/min and a maximum back pressure of 572.5 Pa to maintain a maximum chip temperature of 310.63 K.

scholarly journals Analytical model for prediction of temperature distribution in early age mass concrete

2020 ◽  
Vol 9 (2) ◽  
pp. 359
Author(s):  
Ugwuanyi Donald Chidiebere ◽  
Okafor Fidelis Onyebuchi
Keyword(s):  
Temperature Distribution ◽  
Analytical Model ◽  
Separation Of Variables ◽  
Concrete Structures ◽  
Concrete Block ◽  
Early Age ◽  
Mass Concrete ◽  
Thermally Induced ◽  
Thermal Cracks ◽  
Concrete Placement

Thermally induced cracks have far-reaching implications on the durability of concrete structures. When cement mixes with water, the reaction is exothermic implying the release of heat. In the case of mass concrete structures, quite a substantial increase in internal temperature may be experienced depending on the ambient temperature and cement content in the mix. The objective of the paper is to develop a mathematical model to predict the time dependent temperature profile in early age mass concrete. Mass concrete block was used to verify the model. Type-K thermocouples placed at various positions and digital thermometer was used to monitor the temperature distribution within the mass concrete block at intervals. The highest temperature values occurred within the core of the mass concrete after one day of concrete placement. Analytical model was developed by applying method of separation of variables and orthogonality relation to two dimensional unsteady state heat conduction equations. The model equation was evaluated and using MATLAB based computer programe. The model successfully predicted the temperature variation within the mass concrete with time. It is therefore suitable for use in the assessment of thermal cracks potential in mass concrete structures. 

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