Turbines

[newengr]

I was looking a spec. sheet for a turbine and noticed:
W.R. 73 lb/hp/hr What is W.R.? Work required....
Also when I was looking at the spec sheet it said
150hp @3280/1750 rpm........What is the 3280? The 1750 is rpm right?

Thanks

 

[poetix99]

"WR" is Water Rate, also known as "Steam Rate". It is the amount of steam required for a given unit of work. The units in your example are actually lb/hp-hr, NOT lb/hp/hr.

The expression "Water Rate" is from the perspective of the boiler or more specifically the feedwater, and not the turbine. In any case, the expression persists.

There are different specs that sometimes appear that all look like "water rates". There might be TWR (or TSR), AWR (or ASR), and perhaps others. These are THEORETICAL Water/Steam Rate, and ACTUAL Water/Steam Rate respectively. The Theoretical rate corresponds to the theoretical minimum steam required with an isentropic expansion of the steam.

Regards.

 

[poetix99]

I initially failed to notice part 2 of your posting: the 3280/1750 very likely indicates that the equipment has a speed reducing gearbox between the turbine and the driven equipment. The turbine is running at 3280 rpm and the driven equipment is running at 1750 rpm.