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.

Transient Internal Forced Convection Under Arbitrary Time-Dependent Heat Flux

2013 ◽  
Author(s):  
M. Fakoor-Pakdaman ◽  
M. Andisheh-Tadbir ◽  
Majid Bahrami
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Nusselt Number ◽  
Forced Convection ◽  
Analytical Model ◽  
Time Dependent ◽  
Bulk Temperature ◽  
Fluid Temperature ◽  
Flux Boundary Condition ◽  
Arbitrary Time

A new all-time model is developed to predict transient laminar forced convection heat transfer inside a circular tube under arbitrary time-dependent heat flux. Slug flow condition is assumed for the velocity profile inside the tube. The solution to the time-dependent energy equation for a step heat flux boundary condition is generalized for arbitrary time variations in surface heat flux using a Duhamel’s integral technique. A cyclic time-dependent heat flux is considered and new compact closed-form relationships are proposed to predict: i) fluid temperature distribution inside the tube ii) fluid bulk temperature and iii) the Nusselt number. A new definition, cyclic fully-developed Nusselt number, is introduced and it is shown that in the thermally fully-developed region the Nusselt number is not a function of axial location, but it varies with time and the angular frequency of the imposed heat flux. Optimum conditions are found which maximize the heat transfer rate of the unsteady laminar forced-convective tube flow. We also performed an independent numerical simulation using ANSYS to validate the present analytical model. The comparison between the numerical and the present analytical model shows great agreement; a maximum relative difference less than 5.3%.

Experimental Study of Internal Forced Convection of Ferrofluid Flow in Porous Media

2014 ◽  
Vol 348 ◽  
pp. 139-146 ◽  
Author(s):  
Ashkan Sehat ◽  
Hani Sadrhosseini ◽  
M. Behshad Shafii
Keyword(s):  
Magnetic Field ◽  
Heat Transfer ◽  
Experimental Study ◽  
Porous Media ◽  
Temperature Distribution ◽  
Pressure Drop ◽  
Forced Convection ◽  
Volume Fraction ◽  
Flow In Porous Media ◽  
Tetra Methyl Ammonium Hydroxide

This work presents an experimental study of the effect of a magnetic field on laminar forced convection of a ferrofluid flowing in a tube filled with permeable material. The walls of the tube are subjected to a uniform heat flux and the permeable bed consists of uniform spheres of 3-mm diameter. The ferrofluid synthesis is based on reacting iron (II) and iron (III) in an aqueous ammonia solution to form magnetite, Fe3O4. The magnetite is mixed with aqueous tetra methyl ammonium hydroxide, (CH3)4NOH, solution. The dependency of the pressure drop on the volume fraction, and comparison of the pressure drop and the temperature distribution of the tube wall is studied. Also comparison of the wall temperature distribution, convection heat transfer coefficient and the Nusselt numbers of ferrofluids with different volume fractions is investigated for various Reynolds numbers (147 < Re < 205 ). It is observed that the heat transfer is enhanced by using a porous media, increasing the volume fraction had a similar effect. The pressure coefficient decreases for higher Reynolds number. The effect of magnetic field in four strategies, named modes, on ferrofluid flow through the porous media is presented.

Modeling the Effects of Heat Transfer Processes on Material Strain and Tension in Roll to Roll Manufacturing

2013 ◽  
Author(s):  
Youwei Lu ◽  
Prabhakar R. Pagilla
Keyword(s):  
Heat Transfer ◽  
Temperature Distribution ◽  
Distribution Model ◽  
Tension Zone ◽  
Governing Equations ◽  
Flexible Materials ◽  
Transfer Processes ◽  
Roll To Roll ◽  
Average Modulus ◽  
The Web

This paper develops governing equations for material strain and tension based on a temperature distribution model when the flexible materials (often called webs) are transported on rollers through heat transfer processes within roll-to-roll (R2R) processing machines. Heat transfer processes are employed widely in R2R systems that contain process operations such as printing, coating, lamination, etc., which require heating/cooling of the moving web material. The heat transfer processes introduce the thermal expansion/contraction of the material and changes in the elastic modulus. Thus, the temperature distribution in the moving material affects the strain distribution in the material. Because of change in strain as well as modulus as a function of temperature, tension in the material resulting from elastic strain is also affected by heating/cooling of the web. To obtain the temperature distribution, two basic heat transfer modes are considered: web wrapped on a heat transfer roller and the web span between two consecutive rollers. The governing equations for strain is then obtained using the law of conservation of mass considering the temperature effects. Subsequently, a governing equation for web tension is obtained by assuming the web is elastic with the modulus varying with temperature; an average modulus is considered for defining the constitutive relation between web strain and tension. Since it is difficult to obtain measurement of tension using load cell rollers within heat transfer processes, a tension observer is designed. To evaluate the developed governing equations, numerical simulations for a single tension zone consisting of a heat transfer roller, a web span, and a driven roller are conducted. Results from these numerical model simulations are presented and discussed.

scholarly journals Time dependent temperature distribution model in layered human dermal part

2013 ◽  
Vol 8 (2) ◽  
pp. 66-76
Author(s):  
Saraswati Acharya ◽  
DB Gurung ◽  
VP Saxena
Keyword(s):  
Heat Transfer ◽  
Temperature Distribution ◽  
The Body ◽  
Distribution Model ◽  
Unsteady State ◽  
One Dimensional ◽  
Engineering And Technology ◽  
Governing Differential Equation ◽  
Subcutaneous Tissues ◽  
Sweat Evaporation

The paper developed application of finite element method with linear function in the study of temperature distribution in the layers of dermal part-stratum corneum, stratum germinativum, papillary region, reticular region and subcutaneous tissues as elements. The method is applied to obtain the numerical solution of governing differential equation for one dimensional unsteady state bio-heat transfer using suitable values of parameters that effect the heat transfer in human body. The numerical results obtained are exhibited graphically for various atmospheric temperatures for comparative study of temperature distribution profiles. The loss of heat from the outer surface of the body to the environment is taken due to convection, radiation and sweat evaporation. Kathmandu University Journal of Science, Engineering and Technology Vol. 8, No. II, December, 2012, 66-76 DOI: http://dx.doi.org/10.3126/kuset.v8i2.7327

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.

A Heat Transfer in Iso-Thermal Triangular Channel Filled With Porous Media

2012 ◽  
Author(s):  
S. Negin Mortazavi ◽  
Fatemeh Hassanipour
Keyword(s):  
Heat Transfer ◽  
Porous Media ◽  
Nusselt Number ◽  
Temperature Distribution ◽  
Boundary Conditions ◽  
Forced Convection ◽  
Constant Temperature ◽  
Analytical Solutions ◽  
Apex Angle ◽  
Triangular Channel

This study presents an analysis of forced convection in a porous triangular channel. The flow is laminar, fully developed and assumed to have constant properties. The porous channel has an isotropic matrix and the boundary conditions are fixed with a constant temperature. In this paper, accurate analytical solutions are presented to determine the effects of apex angle and porous media properties on the temperature distribution in a triangular channel along with the Nusselt number NuT.

Feasibility Study of Effective Cooling Through Microchannel Heat Sink (MCHS) and Nanofluid Applications

2018 ◽  
Author(s):  
Darryl Jennings ◽  
Sonya Smith
Keyword(s):  
Heat Transfer ◽  
Pressure Drop ◽  
Forced Convection ◽  
Analytical Model ◽  
Heat Sink ◽  
Convection Heat Transfer ◽  
Microchannel Heat Sink ◽  
Convection Heat ◽  
Ansys Fluent ◽  
Micro Channels

The goal of this research is to present an analytical model of nanostructures and study the effects of their geometry on the performance of micro channels. The pressure drop experienced by micro channels is of interest as it presents a limit on forced convection heat transfer. This work will demonstrate how the presence of nanostructures alleviates pressure drop and results in enhanced cooling capabilities. Multiple transient analyses were performed in ANSYS FLUENT to ascertain performance characteristics of microchannels without the presence of hydrophobic nanostructures. The results were compared to the analytical model developed in this study.

Analytical Method for Temperature Distribution in Buried HDPE Pipe

2012 ◽  
Vol 452-453 ◽  
pp. 1205-1209
Author(s):  
Zheng Li ◽  
Hong Wu Zhu ◽  
Pin Xian Qiu ◽  
Abdennour Seibi
Keyword(s):  
Heat Transfer ◽  
Temperature Distribution ◽  
Analytical Model ◽  
Soil Depth ◽  
Soil Surface ◽  
Fluid Temperature ◽  
Buried Pipe ◽  
Transfer Condition ◽  
Fem Method ◽  
Hdpe Pipe

HDPE pipes have been widely used in industry, which were mostly buried underground. Because of special material properties, which were affected by temperature, it is necessary to get the temperature profile of buried HDPE pipe. Most past solutions for temperature distribution in buried pipe were numerical ones. The aim of this paper was to present a simple analytical model under steady-state heat transfer condition with a new special heat transfer coefficient introduced. FEM method was used to check this model. The influences of fluid temperature, soil surface temperature and soil depth on pipeline temperature were also analyzed. The results showed a good agreement between the analytical model and FEM method. And fluid temperature in pipe was proved to be the key factor that affected the pipe temperature .

scholarly journals Thermal Analysis on Pin-Fins With Hexagonal & Threaded Geometry In Natural and Forced Convection

2020 ◽  
pp. 16-27
Keyword(s):  
Heat Transfer ◽  
Thermal Analysis ◽  
Natural Convection ◽  
Temperature Distribution ◽  
Forced Convection ◽  
Transfer Rate ◽  
Airflow Rate ◽  
Test Panel ◽  
Centrifugal Blower ◽  
Pin Fins

In the present work of heat transfer for hexagonal fins (1mm & 2mm) grooves on surface and threaded fin is addressed. The test has been performed on three different fin geometries having hexagonal (1mm)groove, hexagonal(2mm)groove, threaded fin(0.5mm)pitch and test performed by using a centrifugal blower, test section, heater and test panel and Results are obtained for temperature distribution, effectiveness, efficiencies at a same flow rate of air as it was conducted in forced convection and the same parameters considered for different values are obtained for natural convection with different fins as well. In this experiment for forced convection, the airflow rate is constant i.e, 2.3371 m/sec throughout the experiment. In natural convection, efficiency for the threaded fin is high with 93.89% and effectiveness of hexagonal(2mm)depth fin is 28.11. In forced convection, the efficiency of the threaded fin is high with 81.83% and effectiveness of hexagonal(1mm)depth fin is high with 23.51 was recorded. The heat transfer rate is higher in natural convection is hexagonal(2mm)depth fin with 11.41 watts and 21.75 watts in forced convection with hexagonal(1mm)depth fin

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