Abstract
To elucidate the effects of particulate fouling on the performance of heat equipment and to provide an idea to eliminate it, the mechanism of particle deposition onto a circular and an elliptical cylinder and a tube bundle in turbulent gas flow was experimentally investigated for various flow conditions using the No. 5, JIS Z 8901 (1974) dust (fly ash) for industrial testing. The relationships between fouling and heat transfer characteristics in elliptical cylinders were also discussed on the basis of boundary layer theory.
The size of deposited particles at the stagnation point of a circular and an elliptical cylinder were found to be coarser than those deposited in the wake zone, and the rate of deposition depended on Reynolds number, the turbulent intensity and the slenderness of the ellipses.
The calculated amounts of heat transfer exhibit maximum values at a slenderness of from 0.9 to 1.0, under the assumptions that the ash deposition zone is completely thermally isolated and the Prandtl number of the fluid is always unity.
