calculation of alpha and alphat

calculation of alpha and alphat in the thermophysical and trubulence library

# background

• $\nu$, kinematic viscosity, [m^2/s]
• $\mu$, dynamic viscosity, [kg/(m*s)]
• $\alpha$, thermal diffusivity of enthalpy, [kg/(m*s)], $\alpha=\frac{\lambda}{C_p}$
• $\kappa$ (OF uses kappa), i.e. $\lambda$ (some papers use lambda), Thermal conductivity, [W/(m*K)]
• $P_r=\frac{\nu}{D_t}$ diffusivity of momentum $\nu$ over thermal diffusivity $D_t$, $D_t=\frac{\lambda}{\rho C_p}$. Yields $P_r=\frac{\nu}{D_t}=\frac{\nu}{\lambda/(\rho C_p)}=\frac{\mu}{\lambda /C_p}=\frac{\mu}{\alpha}$
• $L_e=\frac{D_t}{D_k}$ thermal diffusivity $D_t$ over mass diffusion coefficient
• $S_c=\frac{\nu}{D_k}$ diffusivity of momentum $\nu$ over mass diffusion coefficient
Assume $P_r=1$, we get $\lambda=\mu C_p$, and $\alpha=\mu$
Assume $L_e=1$, we get $D_k=\frac{\lambda}{\rho C_p}$
Assume $S_c=1$, we get $D_k=\nu$

## in OpenFOAM

moleWeight_ can be accessed by W(), [kg/kmol]
cp, [J/(kmolK)]
C_p=\frac{cv}{W}, [J/(kg
K)], general use this in many books.
h_s, [J/kmol]
H_s, [J/kg]

# calculation of alpha and alphat

/specie/transport/sutherland/sutherlandTransportI.H

RASModel.H

heThermo.C

alphat()在哪里计算？

KEpsilon.H

KEpsilon.C在构造函数里边：

Author: Yan Zhang