Suggestion of a new model for Newtonian thermal analysis of solidification

Download

index.pdf

Date

2013

Author

Erbaş, Kadir Can

Metadata

Show full item record

Item Usage Stats

200
views

93
downloads

Newtonian thermal analysis (NTA) of solidification is a widely used tool to understand the solidification kinetics of metals. It depends on cooling curve analysis by using heat equations especially Newton’s law of cooling. Calculation of the latent heat of solidification and solid fraction evolution are one of the primary goals of NTA. Several mathematical models have been proposed in the literature for this purpose. However, there are many discussions on the reliability of these models. In this study, latent heats of pure metals, which are calculated from several models, were compared with their literal values. These methods from the literature include Newtonian baseline (NBL), dynamic baseline (DBL), and logarithmic relative temperature baseline (LRTBL), which produced unreliable results for the latent heat values of four types of pure metals (aluminum, lead, tin, and zinc). The most significant restrictions of NTA were determined as the effect of mold’s thermal capacity and variations in the data analysis process. A new model, which was named “two-capacitive system baseline (TCSBL)”, was developed in order to take thermal capacity of the mold into account. This model also includes the radiative contributions and other temperature dependent effects by considering Taylor expansion approach. At the end of the application of the model to several experiments, it was seen that TCSBL is the most reliable model among other models in the literature.

Subject Keywords

Thermal analysis., Solidification., Metals, Heat equation., Molding (Founding).

URI

http://etd.lib.metu.edu.tr/upload/12616688/index.pdf
https://hdl.handle.net/11511/23205

Collections

Graduate School of Natural and Applied Sciences, Thesis

Suggestions

OpenMETU
Core

Experimental investigation and 3D finite element prediction of the white layer thickness, heat affected zone, and surface roughness in EDM process Shabgard, Mohammadreza; Oliaei, Samad Nadimi Bavil; Seyedzavvar, Mirsadegh; Najadebrahimi, Ahmad (2011-12-01) An axisymmetric three-dimensional model or temperature distribution in the electrical discharge machining process has been developed using the finite element method to estimate the surface integrity characteristics of AISI H13 tool steel as workpiece. White layer thickness, depth of heat affected zone, and arithmetical mean roughness consisting of the studied surface integrity features on which the effect of process parameters, including pulse on-time and pulse current were investigated. Additionally, the e...
Development of A Computer Program for The Numerical Investigation of Heat Transfer in A Gasketed Plate Heat Exchanger Sert, İsmail Ozan; Sezer Uzol, Nilay; Güvenç Yazıcıoğlu, Almıla; Kakaç, Sadık (null; 2010-07-14) In this study, a computer program is developed to calculate characteristics of a Chevron type gasketed plate heat exchanger (CTGPHEX) such as: the number of plates, the effective surface area and total pressure drops. The main reason to prefer the use of CTGPHEXs to other various types of heat exchangers is that the heat transfer efficiency is much higher in comparison. Working conditions such as the flow rates and inlet and outlet temperature of both flow sides and plate design parameters are used as an in...
Optimization of the mechanical properties of Ti-6Al-4V alloy fabricated by selective laser melting using thermohydrogen processes BILGIN, Guney Mert; Esen, Ziya; Akin, Seniz Kushan; Dericioğlu, Arcan Fehmi (2017-07-17) 2-step Thermo Hydrogen Process (THP) including hydrogenation and dehydrogenation steps was applied to Ti-6Al-4V alloy fabricated by selective laser melting (SLM) process to refine the microstructure and to increase the ductility of the alloy. It was observed that as-fabricated alloy's surface was composed of oxides of titanium and aluminum, which may alter the hydrogenation kinetics. The hydrogen treatment for 1 hat 650 degrees C, the maximum hydrogen solubility temperature of the alloy, transformed startin...
Application of ab initio methods to secondary lithium batteries Aydınol, Mehmet Kadri; Ceder, G. (1998-01-01) Ab initio methods have started to be widely used in materials science for the prediction of properties of metals, alloys and compounds. These methods basically require only the atomic numbers of the constituent species. Such methods not only provide us with predictions of some of the properties of the material (even before synthesizing it) but also help us in understanding the phenomena that control those properties. The use of ab initio methods in the field of electrochemistry is, however, quite recent and...
Modelling of non-uniform DC driven glow discharge in argon gas Rafatov, İsmail; BILIKMEN, S. (Elsevier BV, 2007-07-16) Physical properties of non-uniform DC-driven glow discharge in argon at pressure 1 torr are analyzed numerically. Spatially two-dimensional axial-symmetric model is based on the diffusion-drift theory of gas discharge. Results presented compare favorably with the classic theory of glow discharges and exhibit good agreement with the experimental result. Comparison with the result of spatially one-dimensional model is performed. (c) 2007 Elsevier B.V. All fights reserved.

Citation Formats

K. C. Erbaş, “Suggestion of a new model for Newtonian thermal analysis of solidification,” Ph.D. - Doctoral Program, Middle East Technical University, 2013.