Question

Water enters the constant 130-mm inside-diameter tubes of a boiler at 7 MPa and 65°C and leaves the tubes at 6 MPa and 450°C with a velocity of 80 m/s. Calculate the velocity of the water at the tube inlet and the inlet volume flow rate. The specific volumes of water at the inlet and exit are 0.001017 m3/kg and 0.05217 m3/kg.

Answer 1

v_1 - 1.55 m/s

flow rate is = 0.0206 m^3/s

Step-by-step explanation:

Given data:

inside diameter is 130 mm

`p_1 = 7MPa`

`T_1 =65 degree C`

`p_2 = 6 MPa`

`T_2 = 450 degree C`

velocity v_2 = 80 m/s

specific volume
`\alpha_1 = 0.001017 m^3/kg`

`\alpha_2 = 0.05217 m^3/kg`

initial velocity can be calculated by equating mass flow rate at inlet and outlet point

`v_1  = (\alpha_1)/(\alpha_2) v_2`

`=(0.001017)/(0.05217) * 80 = 1.55 m/s`

inital flow rate is calculated as

`\dot V_1 =A_1 v_1`

`= (D^2)/(4) \pi v_1`

`= (0.13^2)/(4) \pi 1.55 = 0.0206 m^3/s`