Метод расчета нестационарного теплового потока по сигналу датчика на основе анизотропных термоэлементов из монокристалла висмута

We propose a method for calculating nonstationary heat fluxes using the electric-response signal of a sensor based on anisotropic bismuth single-crystal thermoelements. Using this method, it is possible to approximately calculate the heat flux during a period of time from ∼1 μs to the attainment of a stationary thermal regime. Tests showed that the monitoring of short-term ( t ∼ 1–10 ms) heat fluxes by bismuth-crystal-based sensors with a crystal length to thickness ratio of above 25 ensures a calculation error not exceeding several percent.

Local and Global Simulations of Bridgman and Liquid-Encapsulated Czochralski Crystal Growth

A curvilinear finite volume-based numerical methodology has been developed that can be effectively used for simulation of the Bridgman and Czochralski (Cz) crystal growth processes. New features of grid generation have been devised and added to the original formulation (Zhang et al., 1995, 1996) to make it suitable for global modeling. The numerical model can account for convection in both the melt and the gas phases, convection/radiation in the furnace, and conduction in all solid components. Results for Bridgman growth show that the flow pattern and interface shape strongly depend on thermal conductivities of the crystal, melt, and ampoule materials. Transient simulations have been performed for the growth of Bismuth crystal in a Bridgman-Stockbarger system and the growth of GaAs crystal using liquid-encapsulated Czochralski (LEC) technique. This is the first time that a global high-pressure LEC model is able to account for convective flows and heat transfer and predict the interface shape and its dynamics.