Three-dimensional flow of solution in an industry-size hydrothermal autoclave subjected to non-uniform heating—effects of a baffle on flow and temperature separation

A three-dimensional conjugate model with realistic boundary conditions for flow and heat transfer in an industry scale hydrothermal autoclave

“…This so called isothermal wall assumption has no quantitative evidence to support its validity. Implementing a temperature deviation on the wall inner surface leads to a flow structure that agrees with the flow found in industry autoclaves [10]. Clearly, a determination of the temperature profile at the wall/solution interface is important.…”

“…Since the nutrient concentration variation is usually small, the convection is driven primarily by the temperature difference between the upper and lower chamber walls. Numerical models, including one conjugate model by Roux et al [6] and several isothermal wall models [7][8][9][10], have been developed to investigate the flows in autoclaves. RouxÕs conjugate model, a model of steady laminar flow at low Rayleigh number, predicted a linear temperature distribution at the wall/solution interface from the bottom to the top.…”

“…ChenÕs isothermal wall model [7,8] considered unsteady laminar flow in an autoclave of low aspect ratio while focusing on the effects of the raw material region that was modeled as porous media. The 2-D isothermal wall model [9] and the 3-D one [10] by the present authors focused on the flow of solution in current industry size autoclaves with highly turbulent flows. The 2-D model in [9] assumed uniform temperature on the wall inner surface.…”

“…The 2-D model in [9] assumed uniform temperature on the wall inner surface. The 3-D model in [10] questioned the isothermal wall assumption and superimposed a non-uniform temperature, called a temperature deviation, on the wall inner surface to represent the effects of the asymmetric factors resulting from the autoclave surroundings. The model predicted a one-cell asymmetric flow that agrees with what was found in industry growth practice and the speculated one by Kuznetsov and Lobachev [5].…”

Vortex induced flower-like Ni-Co coating by a hydrothermal approach

“…Li et al [11,12] have investigated the convective flow in hydrothermal autoclaves. Numerical simulation of natural convection in autoclave has been performed by Yoshio et al [5].…”