You determine T_6 by knowing the value of s_6 and the pressure (0.8 MPa). From the steam tables you are able to determine that this is a superheated state, so you go to your superheated tables and by knowing pressure and entropy you can determine temperature.
is it necessary to have a pump(doesn`t state in the problem) before the boiler in a reheat-regenerative rankine cycle with five feedwater? based on the problem i am encountering. PLEASE HELP...
The class was great but my steam table has 0.8mpa which is 8bar and the answer, I got was not corresponding with your answer.. I could not find 188.46 as the temperature, I'm still on the superheated steam
Hi Ron, I'm working on a similar problem that also involves an ideal reheat-regenerative Rankine Cycle. The T-s diagram I came up with included 2s, 4s, 6s and 9s based off an example my professor did in class. Is the reason the diagram for the problem we did in class has the "s" states because the problem includes adiabatic efficiency in the pumps?
You are told that the entry conditions into the Low Pressure Turbine are 0.8MPa and 500C. Looking at the steam tables it is possible to determine that this is a superheated state, from which you go to the superheated steam tables and get your values from there.
Every time I think I've got the hang of this subject, I get it wrong again :( I'm unsure as to how you get h_6, I assumed logically you could multiply the h_g from superheated section by the > 1 x_6 value I used to work out if the point was saturated water/vapour mix or still superheated.
Quality is only defined between the saturated liquid line and the saturated vapor line. You determine h_6 by starting with the known conditions at state 5 (10 MPa and 550C). From the steam tables you know this is superheated. You can determine both enthalpy and entropy at state 5 from the superheated tables (h_5 and s_5). We are not given an isentropic (adiabatic) efficiency for the HP Turbine, thus we can assume that the expansion from state 5 to state 6 is isentropic (i.e., s_5 = s_6). We know the pressure at state 6 is the LP Turbine pressure (0.8 MPa). What you then need to do is go to the steam table and check to see if the value of entropy at state 6 (0.8 MPa) is in the two phase region or the superheated region. If s_6 is greater than the s_g value that you find in the table for 0.8 MPa, you know that you are in the superheated region and you then need to use the superheated tables. You then find the superheated table for the pressure (in this case 0.8 MPa) and you find where s_6 is on this table. It may be between temperatures listed in the table, in which case you will need to interpolate to determine h_6 (and T_6). Also, some tables may not have superheated data at 0.8 MPa. If this is the case you then need to interpolate for the values (h, T, s, etc) at the given pressures (say 0.5 MPa and 1.0 MPa) to 0.8 MPa, and then interpolate for the values of interest (h_6, T_6, etc) using the known value of s_6 - an extremely laborious process! Hope that helps.
I was traveling and have not been able to respond. Please see the response above to vanepico which explains how you determine h_6 - when you use the superheated tables to get h_6 (knowing s_6 = s_5), you can also interpolate for T_6.
You determine T_6 by knowing the value of s_6 and the pressure (0.8 MPa). From the steam tables you are able to determine that this is a superheated state, so you go to your superheated tables and by knowing pressure and entropy you can determine temperature.
good old thermodynamics :')
At state 1 how come Wp1 isnt equal to
Wp1=(1-y)(h2-h1) ???
is it necessary to have a pump(doesn`t state in the problem) before the boiler in a reheat-regenerative rankine cycle with five feedwater? based on the problem i am encountering. PLEASE HELP...
The class was great but my steam table has 0.8mpa which is 8bar and the answer, I got was not corresponding with your answer.. I could not find 188.46 as the temperature, I'm still on the superheated steam
Hi Ron, I'm working on a similar problem that also involves an ideal reheat-regenerative Rankine Cycle. The T-s diagram I came up with included 2s, 4s, 6s and 9s based off an example my professor did in class. Is the reason the diagram for the problem we did in class has the "s" states because the problem includes adiabatic efficiency in the pumps?
How you estimate the temperature 188.46 C (5:59) shouldn't be it 500 C. thanks.
If feed water pressure is also given in the problem, at what point should the pressure be considered.
sir how did you get y or moisture??
please include the table you take the number
Please can you tell me how you got the value in state 8 please
You are told that the entry conditions into the Low Pressure Turbine are 0.8MPa and 500C. Looking at the steam tables it is possible to determine that this is a superheated state, from which you go to the superheated steam tables and get your values from there.
Every time I think I've got the hang of this subject, I get it wrong again :( I'm unsure as to how you get h_6, I assumed logically you could multiply the h_g from superheated section by the > 1 x_6 value I used to work out if the point was saturated water/vapour mix or still superheated.
Quality is only defined between the saturated liquid line and the saturated vapor line. You determine h_6 by starting with the known conditions at state 5 (10 MPa and 550C). From the steam tables you know this is superheated. You can determine both enthalpy and entropy at state 5 from the superheated tables (h_5 and s_5). We are not given an isentropic (adiabatic) efficiency for the HP Turbine, thus we can assume that the expansion from state 5 to state 6 is isentropic (i.e., s_5 = s_6). We know the pressure at state 6 is the LP Turbine pressure (0.8 MPa). What you then need to do is go to the steam table and check to see if the value of entropy at state 6 (0.8 MPa) is in the two phase region or the superheated region. If s_6 is greater than the s_g value that you find in the table for 0.8 MPa, you know that you are in the superheated region and you then need to use the superheated tables. You then find the superheated table for the pressure (in this case 0.8 MPa) and you find where s_6 is on this table. It may be between temperatures listed in the table, in which case you will need to interpolate to determine h_6 (and T_6). Also, some tables may not have superheated data at 0.8 MPa. If this is the case you then need to interpolate for the values (h, T, s, etc) at the given pressures (say 0.5 MPa and 1.0 MPa) to 0.8 MPa, and then interpolate for the values of interest (h_6, T_6, etc) using the known value of s_6 - an extremely laborious process! Hope that helps.
Thank you very much for your help and the videos!
thank you
very helpful
how i can cotact with Dr.ron?
How u know T6 ?
I was traveling and have not been able to respond. Please see the response above to vanepico which explains how you determine h_6 - when you use the superheated tables to get h_6 (knowing s_6 = s_5), you can also interpolate for T_6.
Thank you
tnks