A

cross-sectional area (mm2)

R

tube radius (mm)

c p

specific heat [J/(kg K)]

Re

Reynolds number

c ¯ p

average specific heat [J/(kg K)]

Ri

Richardson number

d

diameter (mm)

T

temperature (K)

G

mass flux [kg/(m2 s)]

u

fluid velocity (m/s)

Gr

Grashof number

v

velocity (m/s)

h

heat transfer coefficient [W/(m2 K)]

Greek symbols

i

enthalpy (J/kg)

λ

Thermal conductivity [W/(m K)]

k

turbulent kinetic energy (m2/s2)

μ

viscosity (g/m s)

m ˙

mass flow rate (kg/s)

ρ

density (kg/m3)

Nu

Nusselt number

Abbreviations / Acronyms

P

pressure (MPa)

GWP

Global Warming Potential

Pr

Prandtl number

LB

Lattice-Boltzmann

q

heat flux (kW/m2)

ODP

Ozone Depletion Potential

Q

heat exchange amount (kW)

SST

Shear Stress Transport

r

radial coordinate (mm)