Calculating Steam Turbine output power

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Discussion Overview

The discussion revolves around calculating the output power of a steam turbine, specifically exploring the relationship between volumetric flow rate and turbine performance. Participants are examining the applicability of various formulas and the implications of using volumetric flow rate in their calculations.

Discussion Character

  • Technical explanation
  • Debate/contested
  • Mathematical reasoning

Main Points Raised

  • One participant presents the formula "W_turbine = m_flow rate * (H_in - H_out)" and inquires about incorporating turbine volumetric flow rate into the calculation.
  • Another participant argues that using volumetric flow rate may not be the correct approach due to the nonlinear properties of steam and water, suggesting the need for reference to these properties.
  • A participant expresses confusion regarding a research paper's mention of a "2 KW output," noting that their calculations using the provided data yield a low result, prompting them to seek alternative formulas that consider volumetric flow rate.
  • Another participant comments on the efficiency of turbines, indicating that higher pressures and temperatures generally lead to lower operating costs, while also suggesting that the 2 KW output may have been a design requirement influenced by fluid constraints.
  • Reference to the Mollier Chart is suggested as a starting point for understanding the thermodynamic properties relevant to the organic fluid in question.

Areas of Agreement / Disagreement

Participants express differing views on the appropriateness of using volumetric flow rate in calculations, with no consensus reached on the best approach or formula to use for determining turbine output power.

Contextual Notes

Participants highlight the complexity of steam and water properties and the potential need for additional research to accurately model turbine performance. There is uncertainty regarding the relationship between input/output data and the expected power output.

Izazo
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TL;DR
What is the formula to calculate turbine output power, which uses the volume flow rate of turbine? (Turbine Physical dimensions are not given)
So I know the formula " W_turbine = m_flow rate * (H_in - H_out) " BUT is there any formula that utilizes the turbine volumetric flow rate (m^3/sec) at the outlet? The following data is available, I just need the formula...
P_in= 2.36 Mpa
P_out= 0.95 MPa
m_flow rate= 0.02 kg/sec
eff_turbine= 70 %
Turbine outlet volume flow rate= 2.4 m^3/sec
 
Last edited:
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You'll never get there that way. The properties of steam and water are nonlinear. You need reference to them.

Can you explain what you are trying to accomplish and why you prefer volume flow as the variable? That sounds like it may be the wrong approach.
 
anorlunda said:
You'll never get there that way. The properties of steam and water are nonlinear. You need reference to them.

Can you explain what you are trying to accomplish and why you prefer volume flow as the variable? That sounds like it may be the wrong approach.
So the main issue is that I have this research paper and that has done some thermodynamic analysis of organic Rankine cycle, and designed it for 2 KW output...I don't understand the meaning of "designed it for 2 KW output", because using the input and output data of turbine from the research paper and using formula "W_turbine = m_flow rate * (H_in - H_out) " the answer is very low.
So, I thought that volume flow rate defines the cost and size of the turbine, so they might have used another formula that utilizes volume flow rate of the turbine...
I
 
In general, the most efficient turbines use the highest possible pressures and temperatures. That minimized operating costs. But it might raise capital costs.

Most likely, they had 2 KW as a requirement. There may be constraints on the pressure and temperature of available fluids.

The place to start is the Mollier Chart for the organic fluid.

https://en.wikipedia.org/wiki/Enthalpy–entropy_chart
But if you want only an order of magnitude estimate, W_turbine = m_flow rate * (H_in - H_out) is a simple energy balance. That might be the best you can do without many days of work to learn about turbine design.
 

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