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ISSN Online: 2377-424X

International Heat Transfer Conference 12
August, 18-23, 2002, Grenoble, France

Design of industrial plant using optimised heat transfer and fluid flow modelling

Get access (open in a dialog) DOI: 10.1615/IHTC12.3370
13 pages

Abstract

Although computational fluid dynamics or heat transfer modelling have the potential to provide powerful design aids for industrial equipment, their application is often limited by the paucity of accurate input data or of clear mappings between variables that can be adjusted in the model and process control parameters. A design method has been developed to use multiple stages of computational models embedded in optimisation procedures to address these issues. The initial stages estimate unknown input data and boundary conditions by effectively tuning the model to match plant measurements. Several optimisation steps may be executed, each being used to estimate a specific group of data. Once the model has been tuned to the real world, it is then used in subsequent optimisation stages that seek to improve the performance of the plant. The improvement is realised by mapping the modified design variables to physical characteristics of the plant.
The overall procedure is demonstrated here for a low pressure casting process. Model tuning involved estimating the feed velocity of melt into the die and heat transfer coefficients between the melt and the die by matching measured and predicted cooling rates. Flow problems, casting hot spots and associated defects were predicted more accurately by the tuned model. This optimised model was then used to adjust thermophysical properties of the die to effect faster cooling rates commensurate with uni-directional solidification. Significant improvements were predicted and these were achieved in the industrial equipment by simulating the optimum thermophysical properties by insulation, chills and cooling circuits.
Application of the model tuning process to the cooling of melt in a cup shaped mould and the quenching of a gear blank are used to explore properties of this step of the procedure. Related developments in commercial packages are discussed.