Mixcoatl Software (Part 1): Coupled Thermal Physics and Mechanics for Efficient Engineering Design

Abstract

As numerical methods and computational capacities improve, there is a greater ability to leverage more complicated physics for engineering design analyses. The primary objectives of this new modeling tool are to (1) implement medium-fidelity physics within a framework that allows for the combination of simplified modeling accuracy with detailed physics tools and (2) enable postprocessing analytics that reduce time to design. These types of tools are considered a requirement to ensure modern designs are not constrained by the tools themselves. One of the novel features of this software is flow searching, which simultaneously resolves the mesh and determines flow parameters that will allow for achieving either pressure equalization or isothermal exit conditions among user-defined groupings of channels. A space nuclear propulsion example using Mixcoatl^TM has been included to illustrate the use of this feature.

Keywords:

• Simulation
• multiphysics
• thermal fluids
• MOOSE
• engineering design

Nomenclature

$A_f$	=	= cross-sectional flow area
$C$	=	= coefficient of discharge
$c_p$	=	= specific heat at constant pressure
$c_s$	=	= specific heat of solid
$D_h$	=	= hydraulic diameter
$d$	=	= orifice diameter
$K$	=	= form loss or porous permeability
$k$	=	= thermal conductivity
$M$	=	= molar mass
$\dot{m}$	=	= mass flow rate
$P$	=	= pressure
$Q$	=	= energy
$q{ }^{\mathrm{\prime }\mathrm{\prime }\mathrm{\prime }}$	=	= volumetric heat generate rate
$T$	=	= temperature
$t$	=	= time
$u$	=	= axial velocity
$V_{solid}$	=	= volume of solid
$X$	=	= mole fraction

Greek

$\beta$	=	= orifice diameter ratio
$ϵ$	=	= expansibility factor
$\mu$	=	= viscosity
$\rho$	=	= density
$\sigma$	=	= porous media temporal coefficient
$\phi$	=	= porosity
$\varphi$	=	= fluid mixture coefficient

Subscripts

$f$	=	= fluid
$s$	=	= solid

Disclosure Statement

No potential conflict of interest was reported by the author(s).