Search results for "Thermal"
showing 10 items of 3576 documents
Design, assembly and characterization of silicide-based thermoelectric modules
2016
ID: 1143 In: Energy conversion and management, 13-21. Summary: Highlights•Novel silicide-based thermoelectric modules were experimentally investigated.•The modules produced high power of 1.04 W at 405 °C and 3.24 W at 735 °C.•An estimated module efficiency of 5.3% represent the highest reported for silicide systems.AbstractSilicides have attracted considerable attention for use in thermoelectric generators due mainly to low cost, low toxicity and light weight, in contrast to conventional materials such as bismuth and lead telluride. Most reported work has focused on optimizing the materials properties while little has been done on module testing. In this work we have designed and tested mod…
Thermophysical-Property-Based Selection of Tool Protective Coatings for Dry Machining of Steels
2003
A method is proposed for determining the optimum cutting conditions in dry turning of carbon and stainless steels using multilayer coated tools for physical criteria such as the maximum temperature of a cutting tool or maximum heat flux. The modified thermal number describing the tool-chip behavior, is introduced. The correlation between the thermal number and the average tool-chip interface temperature and frictional heat flux is examined for both flat-faced and grooved rake configurations. Although not shown here directly, the thermal barrier effect observed for multilayer coatings with an intermediate Al2O3 layer increases the heat partition to the chip at substantially reduced cutting t…
Residual Stresses due to High Temperature Annealing. Mathematical Model and Calculations
2006
The mathematical model is developed for description of thermomechanical processes at cooling during high temperature annealing with the known initial temperature distribution (the temperature of holding) and stresses (acquired stresses at the final of a holding). It is taken into account the thermal sensitivity and material hardening at elasto-plastic solid deforming. The methodology based on the finite element method is proposed for solving thermomechanics problems of wide range. The suitable software is developed. At the final stage of annealing a cylindrical solid it is investigated residual stresses being formed on the cooling stage.
A computational approach to evaluate temperature and heat partition in machining with multilayer coated tools
2003
Abstract In this paper, analytical models for estimating the interface temperature and heat partition to the chip in continuous dry machining of steels with flat-faced tools treated with multilayer coatings are presented. The database for modeling includes changes in the thermal properties of both workpiece and substrate/coating materials and the Peclet and Fourier numbers occurring at actual interface temperatures. Process outputs involve the average tool–chip interface temperature, the tool–chip contact length, the friction energy and the heat balance between the moving chip and stationary tool. It was found that the heat partition coefficient varies significantly from 0.65 to 0.8 when us…
Analyses of innovative glass blocks for BIPV: assessment of thermal and optical performance
2015
This paper illustrates the results of the performance analyses conducted on an innovative glass block integrated with thirdgeneration dye-sensitised solar cells (DSCs), designed to enable the construction of translucent and sustainable building envelopes. The analyses include the simulation of both thermal and optical performance with regard to different configurations of the photovoltaic (PV)-integrated glass block, and the results obtained are presented using two different programs: Comsol Multiphysics and WINDOW. The configurations may differ – for example, because of the position of the module inside the glass block, the type of DSC module used (composition, transparency, design) and th…
Prediction of friction and heat flow in machining incorporating thermophysical properties of the coating–chip interface
2004
Abstract This paper deals with an experimental and analytical investigation into the thermodynamically activated effects influencing the behaviour of the multi-layered coated tool rake face during orthogonal cutting of ferromagnetic and paramagnetic steels. Temperature measurements on the tool rake face using a thermocouple-based technique and identification of the contact zone by means of computer image processing were carried out. New methodology for assessing friction and the amount of thermal energy generated when machining with a coated tool insert with natural and restricted contact coupled with a metallic chip, using thermophysical properties of the sliding materials is developed in …
Finite element modelling of temperature distribution in the cutting zone in turning processes with differently coated tools
2005
Abstract The aim of this study is to check the applicability of various simulation models to obtain finite element solutions of cutting forces, specific cutting energy and adequate temperatures for a range of coated tool materials and defined cutting conditions. Commercial explicit finite element code Thirdwave AdvantEdge has been used in simulations of orthogonal cutting processes performed by means of uncoated carbide and coated tools. The latter were equipped with progressively increasing number of thin layers including TiC, TiN and Al 2 O 3 films deposited onto ISO P20 carbide substrates. Results showing the tool–chip interfacial friction influencing the temperature distribution fields,…
The Continuous Extrusion Process CONFORM: a full 3D Thermal and Mechanical Analysis
2000
The principle of the Conform extrusion process is based on the action of a rotating wheel that drags and push the feed material by means of the frictional force existing between them. The Conform process has several advantages over the traditional extrusion processes. The preheating phase may be neglected, so that furnaces for heating are not necessary; furthermore, the product is continuous and welding phase of the billets is not required. The influence of three operative parameters, die geometry, velocity and die cooling rate, has been analysed in this paper by means of an “outranking approach” able to give precious indications for the assessment of the process.
CHP (combined heat and power) retrofit for a large MED-TVC (multiple effect distillation along with thermal vapour compression) desalination plant: H…
2016
Abstract Integrated power plants in “dual purpose” configuration may represent a viable option for energy cost abatement of desalted water produced by MED-TVC (Multiple Effect Distillation along with Thermal Vapour Compression). In this paper an existing large MED-TVC plant with a 36,000 m 3 /day capacity is studied: a plant retrofit is designed, based on a steam power plant with condensation and steam extraction used to drive the steam ejector. As the plant operates in CHP (Combined Heat and Power) mode, the possibility to assess the integrated “CHP + MED-TVC” as high efficiency cogeneration according to Directive 2004/8/EC is discussed. Based on a model developed in Engineering Equation S…
Energy Optimization of BIPV Glass Blocks: a Multi-software Study
2017
Abstract The aim of this paper is to show the results of the performance analyses carried out on four patented glass block configurations integrated with third-generation Dye-sensitized Solar Cell (DSC) modules. The analyses take into account the thermal, optical and electrical performance by using three different software (COMSOL Multiphysics, WINDOW, Zemax), also enabling to take into consideration the peculiar three-dimensional geometry of this innovative glazed product. Starting from these results, new configurations improved as for the thermal insulation, are also introduced and studied, in order to make further considerations about the applicability of this building component for the …