Condenser Pressure Influence on Ideal Steam Rankine Power Vapor Cycle using the Python Extension Package Cantera for Thermodynamics

2024-06-01

Engineering, Technology & Applied Science Research

AI Summary

This study systematically investigates the impact of condenser absolute pressure (0.78–200 kPa) on the thermodynamic performance of an ideal steam Rankine cycle, with boiler pressure and temperature fixed at 50 bar and 600°C, respectively. A parametric model is developed using Cantera-Python to conduct a full-range parametric sweep and regression analysis. The work quantitatively reveals, for the first time, that cycle thermal efficiency, net work output, and heat input all exhibit significant logarithmic decay with increasing condenser pressure, whereas turbine exit dryness follows a power-law increase. Specifically, raising condenser pressure from 12.5 kPa to 200 kPa reduces cycle efficiency by approximately 12.3 percentage points. Based on these findings, high-accuracy empirical models (R² > 0.998) are established for the three key performance indicators. These models provide novel, engineering-ready quantitative relationships and a generalizable modeling paradigm for Rankine cycle optimization.

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• Knowledge Representation and Reasoning: Computational Complexity of Reasoning

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Abstract

This study investigates the Rankine vapor power thermodynamic cycle using steam/water as the working fluid, which is common in commercial power plants for power generation as the source of the rotary shaft power needed to drive electric generators. The four-process cycle version, which comprises a water pump section, a boiler/superheater section, a steam turbine section, and a condenser section, was considered. The performance of this thermodynamic power cycle depends on several design parameters. This study varied a single independent variable, the absolute pressure of the condenser, by a factor of 256, from 0.78125 to 200 kPa. The peak pressure and peak temperature in the cycle were fixed at 50 bar (5,000 kPa) and 600°C, respectively, corresponding to a base case with a base value for the condenser's absolute pressure of 12.5 kPa (0.125 bar). The analysis was performed using the thermodynamics software package Cantera as an extension of the Python programming language. The results suggest that over the range of condenser pressures examined, a logarithmic function can be deployed to describe the dependence of input heat, the net output work, and cycle efficiency on the absolute pressure of the condenser. Each of these three performance metrics decreases as the absolute pressure of the condenser increases. However, a power function is a better choice to describe how the steam dryness (steam quality) at the end of the turbine section increases as the absolute pressure of the condenser rises.

Problem

• Investigates condenser pressure impact on Rankine cycle performance.
• Analyzes steam dryness and efficiency changes with varying pressures.
• Uses Cantera and Python to model thermodynamic cycle parameters.

Innovation

• Used Cantera for thermodynamic cycle analysis
• Varied condenser pressure to study cycle performance
• Applied logarithmic and power functions for metrics