UBC Theses and Dissertations
Liquid metal flow in horizontal rods MacAulay, Lyle Campbell
Radioactive tracer techniques have been developed which allow direct in situ observation of the nature of fluid flow in liquid tin contained in a long shallow covered horizontal boat. Extensive series of experiments have been conducted in order to confirm the acceptability and accuracy of the techniques employed. The findings of the investigation establish the dependence of flow velocity on temperature difference across the melt, average melt temperature and total melt length. The flow velocity was observed to increase linearly with the average temperature gradient between the hot and cold ends of the melt. An increase in flow velocity with increasing average melt temperature was also observed. Flow was observed to occur at very small temperature gradients. When the temperature gradient was zero at any point between the hot and cold ends of the melt, two flow cells developed. Convective mass transfer did not occur between these two cells. Autoradiography of quenched specimens showed the flow pattern to be a laminar unicellular longitudinal flow upon which a traverse double cell flow is superimposed. The results of the flow pattern and flow velocity experiments are compared to a modification of Batchelor's solution of thermal convection in a rectangular enclosure. In general, the agreement between the experimental results and the modified solution is good. A separate investigation of the macrosegregation associated with casting structure controlled by forced convection is also presented.
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