KURENAI : Kyoto University Research Information Repository

The asymptotic value of the transient heat transfer coefficient, h a, is
given by Eq.(89). Then the ratio between transient and steady state heat
transfer coefficients is given by,-.
h
ha- StSta- [ x* 11/8(92)
stst 0.623 { 1 - exp(-1.318 x*)}
The h a/hst calculated by Eq.(92) is shown in Fig.4, too.
IL. 9 COMPARISON WITH EXPERIMENTAL DATA
Soliman et al. [16-18] carried out experimentson transient heat
transfer with exponential increasing heat generation rate for a flat plate.
Under turbulent flow condition, they have obtained experimental data of '.._
transient response of heater temperature averaged over the whole length of
the flat plate, Q. They reported the transient heat transfer process can
be'predicted by quasi-steady state assumption with
* ha
forQ 2ha= 1.58
st
where Q, is dimensionless heater length (2, =Qw/u co).
In their analysis, the comparison was made between heater temperatures
obtained from their experiment and those calculated based on Eq .(93).
Therefore, Eq.(93) can be regarded as very rough approximation of transient
heat transfer coefficient, since there are considerable uncertainties in
their experimental data. However it should be noted that experimental
results of Soliman et al. [16-18] show general agreement with the results
obtained in present analysis.
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