Steam condenser turbine exit velocity

[lurks]

I am trying to find the exit velocity of the steam coming out of a steam condenser turbine. The inlet pressure is 1312.46 psia with a temperature of 867.67 F. The exit pressure is 7.84 psia with a temperature of 182.97 F. The mass flow rate through the turbine is 220,000 lbm/hr. Am I right in assuming that I can use the saturated steam tables to find the specific volume at the exit and then divide the mass flow rate by this to get volumetric flow? This would then give me the volumetric flow rate at the point where the pressure and temperature were taken.

Thanks in advance,

lurks

 

[davefitz]

No, you will need to obtain the turibne mfr's data sheet that describes the UEEP used energy endpoint enthalpy( probably 5-10% liquid by weight).

There are 2 velocities to determine- the annulus veleocity as the steam leaves the l-1 row of blades ( needed to caclulate the lost energy due to velocity head)and also the avg velocity enteirng the turbine exhaust duct to the condenser.

"Nobody expects the Spanish Inquisition! "

 

[racookpe1978]

Remember that the 200,000 lbm/hr steam flow rate must be used across the entire steam flow area of the condenser inlet if you are to use that enthalpy value to get an average velocity.

What's the power rating and efficiency of the turbine at 200,000 lbm/hr?

Also, don't extrapolate from that one (maximum) steam flow rate and enthalpy down to lower steam flow velocity values. If you need the velocity at lower power levels (lower flow rates) you need to re-calculate using the actual mass flow at each power level, actual exit enthalpy at that power level, and actual water percent to find approximate velocity for each flow rate.

Now, if you are looking for the exit velocity of the steam across the arched round divertor plates right at the L-0 turbine blades, you need to use THAT specific area of the steam flow across the plates - NOT the entry area of the condenser! Remember that only half of the steam will flow across each divertor plate

 

[stgrme]

davefitz and racookepe1978 are correct. If you need an exact velocity, you will need to know the enthalpy [used energy end point (UEEP); also called turbine end point (TEP). Typically, there will be some moisture in the exhaust steam rather than being dry (saturated) steam. If the turbine has extractions, you will need to deduct the extraction flows from the inlet flow of 220,000 lbm/hr. However, if you only need the maximum possible velocity, you can use the specific volume of saturated steam and the full inlet flow.

Best of luck!