scholarly journals Maximum Temperature in Dry Surface Grinding for High Peclet Number and Arbitrary Heat Flux Profile

2016 ◽  
Vol 2016 ◽  
pp. 1-9 ◽  
Author(s):  
J. L. González-Santander
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Linear Regression ◽  
Peclet Number ◽  
Surface Grinding ◽  
Linear Case ◽  
Maximum Temperature ◽  
Péclet Number ◽  
Asymptotic Expressions ◽  
Flux Profile

Regarding heat transfer in dry surface grinding, simple asymptotic expressions of the maximum temperature for large Peclet numbers are derived. For this purpose, we consider the most common heat flux profiles reported in the literature, such as constant, linear, triangular, and parabolic. In the constant case, we provide a refinement of the expression given in the literature. In the linear case, we derive the same expression found in the literature, being the latter fitted by using a linear regression. The expressions for the triangular and parabolic cases are novel.

scholarly journals Maximum Temperature and Relaxation Time in Wet Surface Grinding for a General Heat Flux Profile

2016 ◽  
Vol 2016 ◽  
pp. 1-14 ◽  
Author(s):  
J. L. González-Santander
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Relaxation Time ◽  
Surface Grinding ◽  
Maximum Temperature ◽  
Fast Method ◽  
Workpiece Surface ◽  
Friction Zone ◽  
Flux Profile ◽  
Wet Surface

We solve the boundary-value problem of the heat transfer modeling in wet surface grinding, considering a constant heat transfer coefficient over the workpiece surface and a general heat flux profile within the friction zone between wheel and workpiece. We particularize this general solution to the most common heat flux profiles reported in the literature, that is, constant, linear, parabolic, and triangular. For these cases, we propose a fast method for the numerical computation of maximum temperature, in order to avoid the thermal damage of the workpiece. Also, we provide a very efficient method for the numerical evaluation of the transient regime duration (relaxation time).

Impact of Reservoir Permeability on Flowing Sandface Temperatures: Dimensionless Analysis

SPE Journal ◽  
2013 ◽  
Vol 18 (04) ◽  
pp. 685-694 ◽  
Author(s):  
J.F.. F. App ◽  
K.. Yoshioka
Keyword(s):  
Heat Transfer ◽  
Temperature Change ◽  
Expansion Coefficient ◽  
Peclet Number ◽  
Maximum Temperature ◽  
Péclet Number ◽  
Dimensionless Analysis ◽  
Reservoir Permeability ◽  
Layer Flow ◽  
The Impact

Summary Layer flow contributions are increasingly being quantified through the analysis of measured sandface flowing temperatures. It is commonly known that the maximum temperature change is affected by the magnitude of the drawdown and the Joule-Thomson expansion coefficient of the fluid. Another parameter that strongly impacts layer sandface flowing temperatures is the layer permeability. Aside from determining the drawdown, the layer permeability also affects the ratio of heat transfer by convection to conduction within a reservoir. The impact of permeability can be represented by the Péclet number, which is a dimensionless quantity representing the ratio of heat transfer by convection to conduction. The Péclet number is directly proportional to reservoir permeability. Through dimensionless analysis, it will be shown that for a given drawdown (based on a dimensionless Joule-Thomson expansion coefficient JTD) the temperature change diminishes at low Péclet numbers and increases at high Péclet numbers. This implies that for low-permeability reservoirs such as shale gas or tight oil, the temperature changes will be minimal (less than 0.1ºF) despite the large drawdowns in many instances. Dimensionless analysis is performed for both steady-state and transient thermal models. Results from multilayer transient simulations illustrate the ability to identify contrasting permeability layers on the basis of the Péclet number effect.

Modeling of Micro Welding Process Using Electron Beam Under High Peclet Number

2010 ◽  
Author(s):  
Satya S. Gajapathi ◽  
Sushanta K. Mitra ◽  
Patricio F. Mendez
Keyword(s):  
Heat Transfer ◽  
Electron Beam ◽  
Peclet Number ◽  
Welding Process ◽  
Heat Transfer Analysis ◽  
Maximum Temperature ◽  
Material Loss ◽  
Nano Technology ◽  
Péclet Number ◽  
Advanced Production

The prospect of micro/nano technology requires the development of advanced production processes which joins them into complex systems to interact with the macro world. This has led to the evolution of micro welding. During the micro welding process, the flow of heat needs to be checked so that the essential mechanical and electrical properties of the material are not lost. Also, the amount of melting and excess evaporation has to be controlled. These can be attained by welding using localized heat sources. In the present work, electron beam micro welding process is studied and heat transfer analysis has been carried out numerically, to obtain the temperature distribution in the material. For a specified depth of melting, the effect of Peclet number on the welding process is investigated. The study shows that the high Peclet number electron beam micro welding process provides two important advantages — Control of the maximum temperature on the surface which prevents excess material loss, and limited heat transfer under the beam.

Heat Transfer of Power Law Fluid at Low Peclet Number Flow

1983 ◽  
Vol 105 (3) ◽  
pp. 542-549 ◽  
Author(s):  
Vi-Duong Dang
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Power Law ◽  
Peclet Number ◽  
Wall Heat Flux ◽  
Power Law Fluid ◽  
Axial Conduction ◽  
Péclet Number ◽  
Constant Wall Heat Flux ◽  
Number Flow

An exact solution is presented for the temperature distribution and local Nusselt number of power law fluid in conduit at low Peclet number flow by considering axial conduction in both the upstream and the downstream regions while keeping the wall at constant temperature. Solutions are also reported for the parallel plate geometry for the aforementioned heat transfer condition and for constant wall heat flux boundary condition. The order of importance of axial conduction is established for different geometries and different boundary conditions. The effect of axial conduction is more significant when power law model index, s, increases for constant wall heat flux case, but the effect changes with Peclet number for constant wall temperature case.

scholarly journals Efficient Series Expansions of the Temperature Field in Dry Surface Grinding for Usual Heat Flux Profiles

2017 ◽  
Vol 2017 ◽  
pp. 1-13 ◽  
Author(s):  
Juan Luis González-Santander
Keyword(s):  
Heat Flux ◽  
Temperature Field ◽  
Numerical Evaluation ◽  
Numerical Procedure ◽  
Constant Heat Flux ◽  
Surface Grinding ◽  
Maximum Temperature ◽  
Series Expansions ◽  
Constant Heat ◽  
Flux Profile

In the framework of Jaeger’s model for heat transfer in dry surface grinding, series expansions for calculating the temperature field, assuming constant, linear, triangular, and parabolic heat flux profiles entering into the workpiece, are derived. The numerical evaluation of these series is considerably faster than the numerical integration of Jaeger’s formula and as accurate as the latter. Also, considering a constant heat flux profile, a numerical procedure is proposed for the computation of the maximum temperature as a function of the Peclet number and the depth below the surface. This numerical procedure has been used to evaluate the accuracy of Takazawa’s approximation.

A Numerical Model for Heat Transfer in Dry and Wet Grinding Based on the Finite Difference Method and Jet Cooling

2019 ◽  
Vol 12 (4) ◽  
Author(s):  
Mohammadreza Kadivar ◽  
Mohammadali Kadivar ◽  
Amir Daneshi
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Finite Difference ◽  
Finite Difference Method ◽  
Peclet Number ◽  
Material Removal ◽  
Flux Flow ◽  
Péclet Number ◽  
Heat Partition ◽  
Simulation Results

Abstract Grinding is a promising machining method for finishing workpieces that need a smooth surface with tight tolerances. Due to the high thermal energy generated in the grinding zone, an accurate prediction of workpiece temperature plays a crucial role in the design and optimization of the grinding process. Finite difference method (FDM) is used for simulating the temperature distribution in a workpiece subjected to shallow grinding using a DuFort–Frankel explicit scheme. Moreover, two simple methods, one for modeling the effect of material removal in shallow grinding and the other for calculating the heat partition, are presented. A semi-empirical correlation of cooling jet is applied to calculate the convection heat transfer coefficient (CHTC) over the grinding surface. Experiments were carried out to verify the simulation results, and a good agreement was observed between the simulation and experimental data. An analysis of the results indicated that the misestimation of workpiece temperature could occur when the effect of the material removal rate is not considered in the simulation. The simulation results showed that the heat flux flow is one-dimensional for a high Peclet number, while a two-dimensional heat flux flow prevails for a low Peclet number. The results revealed that reducing the Peclet number and extending the depth of cut increase the heat partition. The study of wet grinding demonstrated that, for efficient cooling, the coolant should be applied directly to the contact zone. Moreover, using water-based emulsion as a coolant was more effective than palm and sunflower oils.

scholarly journals Experimental Determination of the Heat Transfer Coefficient of Real Cooled Geometry Using Linear Regression Method

Energies ◽  
2020 ◽  
Vol 14 (1) ◽  
pp. 180
Author(s):  
Asif Ali ◽  
Lorenzo Cocchi ◽  
Alessio Picchi ◽  
Bruno Facchini
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Heat Transfer Coefficient ◽  
Linear Regression ◽  
Surface Temperature ◽  
Transfer Coefficient ◽  
External Surface ◽  
Internal Surface ◽  
Regression Method ◽  
Thermal Transient

The scope of this work was to develop a technique based on the regression method and apply it on a real cooled geometry for measuring its internal heat transfer distribution. The proposed methodology is based upon an already available literature approach. For implementation of the methodology, the geometry is initially heated to a known steady temperature, followed by thermal transient, induced by injection of ambient air to its internal cooling system. During the thermal transient, external surface temperature of the geometry is recorded with the help of infrared camera. Then, a numerical procedure based upon a series of transient finite element analyses of the geometry is applied by using the obtained experimental data. The total test duration is divided into time steps, during which the heat flux on the internal surface is iteratively updated to target the measured external surface temperature. The final procured heat flux and internal surface temperature data of each time step is used to find the convective heat transfer coefficient via linear regression. This methodology is successfully implemented on three geometries: a circular duct, a blade with U-bend internal channel, and a cooled high pressure vane of real engine, with the help of a test rig developed at the University of Florence, Italy. The results are compared with the ones retrieved with similar approach available in the open literature, and the pros and cons of both methodologies are discussed in detail for each geometry.

Modeling temperature rise in multi-track reciprocating frictional sliding

2021 ◽  
pp. 135065012098823
Author(s):  
Thierry A Blanchet
Keyword(s):  
Temperature Rise ◽  
Peclet Number ◽  
Maximum Temperature ◽  
Uniform Heat Flux ◽  
Heat Accumulation ◽  
Stroke Length ◽  
Péclet Number ◽  
Maximum Temperature Rise ◽  
Rectangular Patch ◽  
Accumulation Effect

As in various manufacturing processes, in sliding tests with scanning motions to extend the sliding distance over fresh countersurface, temperature rise during any pass is bolstered by heating during prior passes over neighboring tracks, providing a “heat accumulation effect” with persisting temperature rises contributing to an overall temperature rise of the current pass. Conduction modeling is developed for surface temperature rise as a function of numerous inputs: power and size of heat source; speed and stroke length, and track increment of scanning motion; and countersurface thermal properties. Analysis focused on mid-stroke location for passes of a square uniform heat flux sufficiently far into the rectangular patch being scanned from the first pass at its edge that steady heat accumulation effect response is adopted, focusing on maximum temperature rise experienced across the pass' track. The model is non-dimensionalized to broaden the applicability of the output of its runs. Focusing on practical “high” scanning speeds, represented non-dimensionally by Peclet number (in excess of 40), applicability is further broadened by multiplying non-dimensional maximum temperature rise by the square root of Peclet number as model output. Additionally, investigating model runs at various non-dimensional speed (Peclet number) and reciprocation period values, it appears these do not act as independent inputs, but instead with their product (non-dimensional stroke length) as a single independent input. Modified maximum temperature rise output appears to be a function of only two inputs, increasing with decreasing non-dimensional values of stroke length and scanning increment, with outputs of models runs summarized compactly in a simple chart.

scholarly journals HEAT EXCHANGE IN A PLANE CHANNEL IN A TURBULENT FLOW REGIME IN THE CASE OF SMALL VALUES OF PRANDTL NUMBER ACCORDING TO DATA OF DIRECT NUMERICAL SIMULATION

2021 ◽  
Vol 56 ◽  
pp. 57-60
Author(s):  
Yurii G. Chesnokov ◽  
Keyword(s):  
Heat Transfer ◽  
Numerical Simulation ◽  
Prandtl Number ◽  
Direct Numerical Simulation ◽  
Transfer Process ◽  
Peclet Number ◽  
Plane Channel ◽  
Heat Transfer Process ◽  
Flat Channel ◽  
Péclet Number

Using the results obtained by the method of direct numerical simulation of the heat transfer process in a flat channel by various authors, it is shown that at small values of Prandtl number quite a few characteristics of the heat transfer process in a flat channel depend not on Reynolds and Prandtl numbers separately, but on Peclet number. Peclet number is calculated from the so-called dynamic speed

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