The Effect of Thermophoresis on the Particle Deposition on a Cylinder
The effect of thermophoresis on the particle deposition on a cooled cylinder
in non-isothermal laminar gas ow has been studied using Direct Numerical
Simulations (DNS). Simulations where thermophoresis have been taken into
account for different Stokes numbers and particle-to-gas thermal conductivity
ratios, Λ, have been performed at Reynolds number Re = 380. In addition
reference cases, simulations where thermophoresis have not been taken into
account, have been performed both for isothermal and non-isothermal ow
for Re = 20 and Re = 380.
The ratio between the front side particle impaction efficiency in the non-
isothermal reference case and the isothermal reference case for the smallest
Stokes numbers considered was expected to be proportional to the ratio of
the free stream temperature and the cylinder temperature, according to an-
analytical considerations. The simulations for Re = 20 was in good agreement
with this relation, but for Re = 380 the front side particle impaction efficiency for the smallest particles was lower in the non-isothermal reference
case compared to the isothermal reference case. This is believed to have
been caused by inaccuracies in the numerical method for the non-isothermal
simulation at Re = 380.
Thermophoresis was not found to affect the particle impaction for the
largest Stokes numbers. For intermediate and small Stokes numbers the effect of thermophoresis depended on Λ. The particle impaction efficiency was
significantly higher, both for the front side and the back side, in the ther-
mophoretic simulations compared to the non-isothermal reference case for
particles with Λ = 1 and Λ = 100. The particle impaction efficiency for
particles with Λ = 1000 was lower, both for the front side and the back side,
in the thermophoretic case compared to the non-isothermal reference case.
Place, publisher, year, edition, pages
Institutt for fysikk , 2012. , 67 p.
ntnudaim:7429, MTFYMA fysikk og matematikk, Teknisk fysikk
IdentifiersURN: urn:nbn:no:ntnu:diva-18489Local ID: ntnudaim:7429OAI: oai:DiVA.org:ntnu-18489DiVA: diva2:565977
Støvneng, Jon Andreas, FørsteamanuensisHaugen, Nils Erland