Question

A well-insulated tank in a vapor power plant operates at steady state. water enters at inlet 1 at a rate of 125 lb/s at 14.7 lbf/in2 . make-up water to replenish steam losses from the plant enters at inlet 2 at a rate of 10 lb/s at 14.7 lbf/in2 and 60of. water exits the tank at 14.7 lbf/in2 . neglecting kinetic and potential energy effects,

What is the mass flow rate, in lb/s, of the water exiting the tank in a vapor power plant?
a) 135 lb/s
b) 115 lb/s
c) 1350 lb/s
d) 1150 lb/s

Answer 1

The mass flow rate of the water exiting the tank is calculated using conservation of mass, by adding the mass flow rates entering the tank, which gives us 135 lb/s.

Step-by-step explanation:

The mass flow rate of the water exiting the tank in a vapor power plant can be determined using the principle of mass conservation. Considering water enters at inlet 1 at 125 lb/s and at inlet 2 at 10 lb/s, and assuming no other sources or sinks within the system, the mass flow rate out of the tank must equal the total mass flow rate entering the tank.

Therefore, we need to simply add the mass flow rates entering the tank to find the mass flow rate exiting the tank:

• Mass flow rate at inlet 1: 125 lb/s
• Mass flow rate at inlet 2: 10 lb/s

Adding these together gives:

Mass flow rate exiting = 125 lb/s + 10 lb/s = 135 lb/s.

Hence, the correct answer is (a) 135 lb/s.