We have made fundamental contributions towards understanding heat transfer and fluid flow during melting and freezing. We have developed an enthalpy-based Lattice Boltzmann model for phase transition processes in the presence of convective transport. We have developed a systematic and generalized procedure for mathematical formulation of latent heat functions, as applicable for enthalpy-based solidification modeling of multicomponent alloy systems. The method uses a metallurgically appropriate thermo-solutal coupling strategy, in conjunction with updating of respective phase fractions, in order to obtain solutions of field variables that are consistent with the pertinent phase-change morphology. With the generalized algorithms, we have expanded the utilitarian scope of the enthalpy-based methods manifold and this is considered to be one of the most significant contributions in the enthalpy-based solidification modelling techniques. We have also contributed towards developing enthalpy-based models for dendritic growth as well as multi-scale solidification models based on homogenization techniques. These models have been applied successfully to understand the defects in casting processes of leading Industrial houses.

We have also proposed new theory to describe the stochastic multi-scale dynamics of dynamically evolving particles in a complex fluid flow. This effort, for the first time, related fragmented dendritic transport with convection in a solidifying melt and paved the way of defining new microstructures in solidifying systems.

References

• S. Chakraborty and D. Chatterjee, “An enthalpy-based hybrid lattice-Boltzmann method for modelling solid-liquid phase transition in presence of convective transport”, Journal of Fluid Mechanics, vol. 592, pp. 155-176, 2007
• S. Ganguly and S. Chakraborty, “A Generalized Enthalpy-based macro-model for Ternary Alloy Solidification Simulations”, Numerical Heat Transfer B, vol. 51, pp. 293-313, 2007
• S. Chakraborty and A. Kumar, “Transport mechanisms of falling crystals detached from the freezing front during solidification of a hypereutectic binary mixture”, Physical Review Letters, vol. 95, pp. 024504 (1-4), 2005
• S. Ganguly and S. Chakraborty, “A Generalized Formulation of Latent Heat Functions in Enthalpy-Based Mathematical Models for Multicomponent Alloy Solidification Systems”, Metallurgical and Materials Transactions B, vol. 37B, pp. 143-145, 2006
• J. Bhattacharya, P. Dutta and S. Chakraborty, “An enthalpy model for simulation of dendritic growth”, Numerical Heat Transfer B, vol. 50, pp. 59-78, 2006
• D. DasGupta, S. Basu and S. Chakraborty, “Effective property predictions in multi-scale solidification modeling using homogenization theory”, Physics Letters A, vol. 348, pp. 386-396, 2006
• D. Chatterjee and S. Chakraborty, “An enthalpy-based lattice Boltzmann model for diffusion dominated solid-liquid phase transformation”, Physics Letters A, vol. 341, pp. 320-330, 2005
• D. Chakraborty and P. Dutta., “A generalized formulation for evaluation of latent heat functions in enthalpy-based macroscopic models for convection-diffusion phase change process”, Metallurgical and Materials Transactions B, vol. 32B, pp. 562-564, 2001