Question

A throttle governed steam engine develops 15 kW with 280 kg power of steam and 35 kW with 520 kg per hour of steam. The steam consumption in kg per hour when developing 20 kW of power will be nearly
1. 340 kg/hr
2. 150 kg/hr
3. cannot be calculated
4. 280 kg/hr

Answer 1

Correct Answer - Option 1 : 340 kg/hr

Concept:

Relationship between steam consumption per hour (m) and the indicated power (IP) is given by:

m = a + b × I.P

Where a and b are constant 

Calculation:

Given:

m₁ = 280 kg/hr, m₂ = 520 kg/hr, (I.P)₁ = 15kW, (I.P)₂ = 35 kW

Substituting in the above equation

280 = a + b × 15       ----(i)

520 = a + b × 35      ----(ii)

solving equation (i) and (ii) we get

a = 100, b = 12

m = 100 + 12 × I.P

∴ steam consumption when developing 20 kW of power

m = 100 + 12 × 20 = 340 kg/hr