Effects of nozzle friction

Friction losses in a nozzle depend upon various aspects. The effects of nozzle friction are as follows:

1. Reduction in enthalpy drop: Friction in nozzle affects its efficiency. As the efficiency of nozzle is the ratio of actual enthalpy drop to ideal enthalpy drop in nozzle, the friction in nozzle decreases the enthalpy drop.

2. Reduction in exit velocity: The kinetic energy of the steam increases at the expense of its pressure energy in the steam nozzle. Some kinetic energy gets lost to overcome the friction in nozzle. Therefore, exit velocity of steam decreases due to nozzle friction.

3. Increase in specific volume: Specific volume of steam can be defined as the of volume of steam per unit weight of the steam. Specific volume increases due to nozzle friction. 

4. Decrease in mass flow rate: As the friction in nozzle slows down the flow of steam in it, the mass flow rate also decreases due to nozzle friction.