Question

A rigid container of volume 0.2 m3 contains 5 kg of water at 20 ◦C. The maximum allowable pressure of the container is set at 10 MPa. The system is now connected to a heat source, which transfers heat at a rate of 1000 W to the container. How long will the container survive?

Answer 1

Since the container is rigid the specific volume will remain unchanged

Specific volume (V) =0.2/5 = 0.04 m3/Kg

Now we will look up in steam table and find the value of enthalp corresponding to the above value of secific volume and Pressure of 10 MPa

T = 630 oC and H=3699.43 KJ/Kg

Total enthalpy = 3699.43*5 =18497 KJ = 18497150 Joule

Let the time which the container cam survive be "t" second

Hence energy supplied till the point where container breaks will be

1000*t =18497150

t =18497.15 seconds =308.285mins =5.138 hours