Experimental Research of Non-Stationary Temperature Fields of the Heat-Exchange Surface of Once-Through Steam Generating Channels

摘要

Heat exchange processes in channels of once-through steam generators can occur in the nonstationary operating regimes connected with pulsations of feedwater flow rate. Known methods of elimination of interchannel instability cannot provide its absence in all range of operating regimes of nuclear power plants (NPP). Thereof, channels of once -through steam generators with low evaporative capacity produce steam in the conditions of interchannel instability. Feedwater flow rate pulsations result in temperature pulsations of heat-exchange surface and finally define its durability. Therefore the dependence of statistical characteristics of temperature pulsations on regime parametres of working medium, amplitudes and frequencies of feedwater flow rate pulsations is actual. Experimental research has been done on experimental model of once-through steam generate channel, equipped with micro thermocouples. The plunger type pulsator has been applied to cause compelled fluctuations of feedwater flow rate. Time sampling of temperature fields, pressure and the feedwater flow rate have been recorded by means of data acquisition & processing system. Experimental research has been done in the following range of parameters: feedwater pressure up to 6 МPа, feedwater temperature 50-150 ℃, amplitude of pulsations of flow rate 0÷100 %, frequency of pulsations 0÷3 Hz.