ISSN Online: 2377-424X
ISBN Print: 0-89116-299-2
International Heat Transfer Conference 7
HEAT TRANSFER AND PRESSURE DROP OF PEBBLE BEDS UP TO HIGH REYNOLDS NUMBER
要約
Heat and mass transfer of a randomly packed
pebble bed has been measured in the range of Reynolds
number 1 < Re < 3 × 105. The naphthalene sublimation in air (Sc = 2,53, 1 < Re < 104) as well as the electrically heated single sphere in an unheated packing (Pr = 0,7; 103 < Re < 3 × 105)
were applied. In the overlapping range both
methods exhibit the same result. While for
Re > 500 the agreement of the present results
with those predicted by Gnielinski is excellent
the deviation increases with decreasing Re. The
pressure drop was measured in the range 250 < Re/
(1−ε) < 5 × 105. For Re/(1−ε) < 105 the pressure
drop coefficient correlated well with established
equations while at very high Re a constant
value of Ψ = 1.75 was observed for the
first time.