How Can Efficiency Be Maximized in a Velocity Compounded Impulse Steam Turbine?

[paul89]

hii frends,

im a doing a project on the efficiency improvement of a velocity compounded impulse steam turbine. we plan 2 do that by varying the input mass flow rate of steam and finding out the particular mass flow rate at which maximum efficiency is attained.

the data i could collect were: rated power of turbine = 820 kw
speed at full load = 5000 rpm
mass flow rate at full load = 11.3 tn/hr
speed at normal load = 3000 rpm
mass flow rate at normal load= 8.1 tn/hr

to find out the efficiency u need to find out the output shaft power 4 tat mass flow rate
the formula for output shaft power is = (2*3.14*N*T)/60000 KW
but the problem is tat turbine is not fitted with any device(eg dynamometer) 2 find out the torque at the shaft

is there any other method 2 find out the output torque developed on the turbine shaft?
are there any other formulas 2 find out the output power corresponding 2 the input mass flow given?
or are there any other suggestions 2 find out the max efficiency point. pls suggest

 

[russ_watters]

What is the shaft driving?

 

[paul89]

shaft is driving a blower

 

[russ_watters]

So why don't you measure the velocity of the air? Do you have a performance curve for the blower (ie, to tell you the efficiency)?

Note, your power output will vary as a cube function of rpm, so you'll want to be careful to make sure you understand what you are measuring. When you vary your mass flow rate, you'll vary your rpm, which will have a huge impact on the torque. I would think either a constant rpm or constant torque scenario would be desirable for this.

 

[paul89]

thanks russ. ill try tat