Question:-
For the fully developed laminar flow and heat transfer in a uniformly heated long circular tube, if the flow velocity is doubled and the tube diameter is halved, halved, the heat transfer coefficient will be
Option (A)
Double of the original value
Option (B)
half of the original value
Option(C)
Same as before
Option(D)
Four times of the original value
Correct Option:
(A)
Question Solution:
Nu = 4.36 for constant heat flux in laminar flow through pipe
Hd/k = 4.36 ha(1/d) (h2/h1) = d1/d2 = 2d/d
h2 = 2h1 the heat transfer coefficient gets doubled
question-answer-faq-6087