Experimental study of natural circulation flow instability induced by flow boiling and loop circulation

Abstract An experimental study of natural circulation flow instability has been carried out to investigate instability modes at low pressure. Water in the primary loop is heated in a single macro-channel and condensed in a tube-shell shape condenser by circulating coolant in the secondary loop. Two kinds of flow instability modes are identified: flow instability induced by flow boiling in the heated channel and flow instability induced by loop circulation. Flow boiling instabilities are found at three exit vapor qualities: xe