Critical flow subcooling region

Critical flow. The critical flow condition depends on the subcooling region. 

This is a high subcooling region and the flow is critical.)... 

The results indicate that as the Froude number decreases, the flow becomes unstable, where zero Froude number is for horizontal flows, and negative Froude number is for downflow. On the other hand, the critical subcooling number decreases with the increase in the exit loss coefficient, implying that the stable region is smaller. Both these results have been also confirmed for density-wave instabilities. 

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