TFTR vacuum vessel bellows cooling system heat transfer and flow distribution tests

To verify the adequacy of the proposed cooling system, two full-scale models of sections of a typical vacuum vessel bellows assembly were constructed. One model, constructed of wood, was dedicated to measuring the flow distribution within the bellows. The other model, consisting of two Inconel 625 convolutions which were heated electrically, was used to develop a heat transfer coefficient correlation for the flow range of interest (i.e., the ''transition'' zone). The test results indicated that the flow distribution is virtually uniform, the flow is stable, and the heat transfer coefficient can be as low as one-tenth of that given by the Dittus-Beolter correlation for fully developed turbulent flow. It was concluded that the proposed system (3600 cfm of gaseous nitrogen) can satisfy its design requirements