Natural Heat Transfer Check - MapleSim Help

Natural Heat Transfer Check

Accessory component to check the heat transfer coefficient of Natural convection

 Description The Natural Heat Transfer Check component models the heat transfer coefficient calculation of Natural convection. Before using HeatConvection component, you can check how to calculate the heat transfer coefficient internally.
 Equations Average temperature is : $T=\frac{\mathrm{Tin}\left[1\right]-\mathrm{Tin}\left[2\right]}{2}$   Heat transfer coefficient of Natural convection is calculated with : ( $h=\frac{\mathrm{Nu}\cdot k}{X}$ ) ( $\mathrm{Nu}={\begin{array}{cc}\mathrm{C__lam}\cdot {\mathrm{Ra}}^{\mathrm{n__lam}}& \mathrm{Ra}\le \mathrm{Threshold}\\ \mathrm{C__tur}\cdot {\mathrm{Ra}}^{\mathrm{n__tur}}& \mathrm{otherwise}\end{array}\mathrm{__}$) ( $\mathrm{Ra}=\mathrm{Gr}\cdot \mathrm{Pr}$ ) ( $\mathrm{Gr}$ and $\mathrm{Pr}$ and $k$ is calculated from $\mathrm{pin}$ and $T$ )   Output is : $\mathrm{out}=h$   For details about the calculation of Fluid properties, see Fluid Properties Check.

Variables

 Symbol Units Description Modelica ID $\mathrm{T__}$ $K$ Averaged temperature between Tin[1] and Tin[2] $h$ $\frac{W}{{m}^{2}\cdot K}$ Heat transfer coefficient $\mathrm{Nu}$  Nusselt number $\mathrm{Pr}$  Prandtl number $\mathrm{Gr}$  Grashof number $\mathrm{Ra}$  Rayleigh number $k$ $\frac{W}{m\cdot K}$ Thermal conductivity

Connections

 Name Units Condition Description Modelica ID $\mathrm{pin}$ $\mathrm{Pa}$ - Pressure input pin $\mathrm{Tin}\left[2\right]$ $K$ - Temperature inputs Tin[2] $\mathrm{out}$ $\frac{W}{m\cdot K}$ - Heat transfer coefficient of Natural convection out

Parameters

 Symbol Default Units Description Modelica ID $X$ $0.1$ $m$ Streamwise length X ${C}_{\mathrm{lam}}$ $0.59$  Gain parameter for Reynolds number in the generalized experimental equation of Natural convection generalized equation when Fluid is laminar. C_lam ${n}_{\mathrm{lam}}$ $\frac{1}{4}$  Exponent parameter for Reynolds number in the generalized experimental equation of Natural convection generalized equation when Fluid is laminar. n_lam ${C}_{\mathrm{tur}}$ $0.1$  Gain parameter for Reynolds number in the generalized experimental equation of Natural convection generalized equation when Fluid is Turbulent. C_tur ${n}_{\mathrm{tur}}$ $\frac{1}{3}$  Exponent parameter for Reynolds number in the generalized experimental equation of Natural convection generalized equation when Fluid is Turbulent. n_tur $\mathrm{Threshold}$ ${10}^{9}$  Threshold value for Reynolds number to define Laminar or Turbulent. TH

Initial Conditions

 Symbol Units Description Modelica ID $K$ Initial condition of the averaged temperature T(0)