KURENAI : Kyoto University Research Information Repository

lI . 1 INTRODUCTION
As described in the previous chapter, heat transfer under pxpo-
nential power increase is important in relation to reactivity accident
in a nuclear reactor. Therefore, the transient boiling phenomena have
been studied in detail. However, when the power transient accident occurs
in a pressurized water reacter or in a liquid metal cooled reactor,.. the
heat transfer process in aninitial stage is considered to be of non-boiling
forced convective transient heat transfer. Therefore, in analysing the
problems associated with a reactivity accident, the knowledge of
transient non-boiling heat transferis also indespensable. In the previous
chapter, some experimental results on non-boiling transient heat transfer
coefficient have been reported. However, the obtained correlation was
purely experimental one and not based on the detailed analysis of heat
transfer mechanisms. Therefore, in this chapter, an analytical study
has been carried out on the transient non-boiling forced convective heat
transfer under exponentially increasing heat flux.
There have been some analytical and experimental works on transient
non-boiling heat transfer [1]. Concerning the transient heat transfer analysis
in flows in round tube, annulus and parallel plate, analytical and numerical ana-
lyses have been carried out by Siegel [2-5] , Sparrow and Siegel [6] , Perlmutter and
Siegel [7] , Siegel and Perlmutter [8] , Namatame [9] and Kawamura et al.
[10-12]. Kawamura et al. [10-12] also conducted experiments in annu-
lus. On the other hand, several works have been carried out for flat
plate by Cess [13] , Goodman [14] , Adams et al. [15] , Soliman et al. [16-18] ,
Chao et al. [19,20] , Ishiguro et al'. [21,22] and Hanawa [23-26] . In most
113