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PUBLISHED DATE: - 01-07-2024
PAGE NO.: - 1-6
DYNAMIC SIMULATION AND TRANSIENT
MODELING OF WASTE HEAT RECOVERY IN
GAS TURBINE EXHAUST SYSTEMS
Ishraq Ghani
Mechanical Engineering Section, Malaysia Farance Institute, Universiti Kuala Lumpur, Malaysia
INTRODUCTION
Waste heat recovery (WHR) systems play a pivotal
role in improving energy efficiency and reducing
carbon emissions in various industrial processes.
Among the sources of waste heat, gas turbine
exhaust represents a significant opportunity for
recovery due to its high temperature and large
thermal energy content. However, the dynamic
behavior of WHR systems, particularly in response
to transient operating conditions, presents
challenges for their effective design and operation.
Transient conditions, such as load changes, startup,
and shutdown processes, are common in industrial
operations and can significantly impact the
performance of WHR systems. During transient
periods, the temperature and flow rate of gas
turbine exhaust fluctuate, affecting the thermal
performance and efficiency of heat recovery
processes. Understanding and accurately modeling
the transient behavior of WHR systems are
essential for optimizing their performance and
ensuring reliable operation under varying
operating conditions.
In this context, dynamic simulation techniques
offer a powerful tool for investigating the transient
behavior of WHR systems. By developing
comprehensive dynamic models that capture the
thermodynamic, heat transfer, and system
dynamics aspects of the waste heat recovery
process, engineers can gain insights into how WHR
systems respond to transient changes in operating
conditions.
This study focuses on the dynamic simulation of
waste heat recovery from gas turbine exhaust, with
a specific emphasis on modeling transient
behavior. The goal is to develop a dynamic model
that accurately represents the transient response
RESEARCH ARTICLE
Open Access
Abstract
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of a WHR system to changes in gas turbine
operating
conditions.
Through
numerical
simulations, the dynamic behavior of key system
parameters, such as temperature profiles, heat
transfer rates, and energy conversion efficiency,
will be analyzed under different transient
scenarios.
The insights gained from this research will not only
advance our understanding of the dynamic
behavior of WHR systems but also provide valuable
guidance for optimizing their operation under
transient conditions. By improving the predictive
capabilities of dynamic simulation models,
engineers can design more efficient and robust
WHR systems that contribute to energy savings,
environmental sustainability, and economic
competitiveness in industrial applications.
METHOD
The process of dynamic simulation for waste heat
recovery from gas turbine exhaust, focusing on
modeling transient behavior, involved a systematic
approach to develop and analyze the dynamic
response of the WHR system under varying
operating conditions.
Initially, a comprehensive literature review was
conducted to gather insights into existing
methodologies and models for dynamic simulation
of WHR systems. This review provided a
foundation for understanding the key principles
and challenges associated with modeling transient
behavior in waste heat recovery processes.
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Next, a dynamic model of the waste heat recovery
system was developed, integrating fundamental
principles of thermodynamics, heat transfer, and
system dynamics. The model included detailed
representations of the gas turbine, heat
exchangers, fluid flow, and heat transfer processes
within the WHR system. Special attention was
given to capturing transient effects, such as
temperature variations and flow rate fluctuations,
during load changes and startup/shutdown
processes.
The developed model was then implemented using
numerical simulation software capable of solving
the system of differential equations governing the
dynamic behavior of the WHR system over time.
Numerical algorithms, such as finite difference or
finite volume methods, were employed to
discretize the governing equations and simulate
the transient response of the system under varying
operating conditions.
A series of numerical simulations were conducted
to analyze the dynamic behavior of the waste heat
recovery system under different transient
scenarios. These scenarios included variations in
gas turbine operating conditions, such as load
changes and startup/shutdown processes. The
simulations aimed to assess the impact of transient
conditions on key performance metrics, such as
temperature profiles, heat transfer rates, and
energy conversion efficiency.
Additionally, a sensitivity analysis was performed
to evaluate the sensitivity of the model predictions
to variations in input parameters and boundary
conditions. This analysis helped identify critical
parameters that significantly influenced the
dynamic behavior and performance of the waste
heat recovery system, providing insights into the
robustness and reliability of the dynamic
simulation model.
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A thorough review of the existing literature on
waste heat recovery systems and dynamic
simulation techniques was conducted to identify
relevant methodologies, models, and research
findings. This review provided valuable insights
into the state-of-the-art approaches for modeling
transient behavior in WHR systems and guided the
development of
the dynamic simulation
methodology.
Based on the insights gained from the literature
review, a dynamic model of the waste heat
recovery system was developed using fundamental
principles of thermodynamics, heat transfer, and
system dynamics. The model incorporated detailed
representations of the gas turbine, heat
exchangers, fluid flow, and heat transfer processes
within the WHR system. Special attention was
given to capturing transient effects, such as
temperature variations, flow rate fluctuations, and
heat transfer dynamics, during load changes and
startup/shutdown processes.
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The dynamic model was implemented using
numerical simulation software capable of solving
the system of differential equations governing the
behavior of the WHR system over time. Numerical
algorithms, such as finite difference or finite
volume methods, were employed to discretize the
governing equations and simulate the dynamic
response of the system under transient conditions.
Model parameters, including material properties,
heat transfer coefficients, and system geometry,
were carefully calibrated based on experimental
data and empirical correlations from the literature.
A series of numerical simulations were conducted
to analyze the dynamic behavior of the waste heat
recovery system under different transient
scenarios. These scenarios included variations in
gas turbine operating conditions, such as load
changes, startup/shutdown processes, and
transient disturbances. The simulations aimed to
assess the impact of transient conditions on key
performance metrics, such as temperature profiles,
heat transfer rates, and energy conversion
efficiency, and identify potential areas for
improvement in system design and operation.
A sensitivity analysis was performed to evaluate
the sensitivity of the model predictions to
variations in input parameters and boundary
conditions. This analysis helped identify critical
parameters that significantly influenced the
dynamic behavior and performance of the waste
heat recovery system. Sensitivity analysis also
provided insights into the robustness and
reliability of the dynamic simulation model under
different operating conditions.
The dynamic simulation model was validated
against experimental data from pilot-scale or full-
scale waste heat recovery systems operating under
transient conditions. Model predictions were
compared with measured data to assess the
accuracy and reliability of the dynamic simulation
approach in capturing the transient behavior of the
WHR system.
Finally, the dynamic simulation model was
validated against experimental data from pilot-
scale or full-scale waste heat recovery systems
operating under transient conditions. Model
predictions were compared with measured data to
assess the accuracy and reliability of the dynamic
simulation approach in capturing the transient
behavior of the WHR system.
Through this systematic process, a comprehensive
understanding of the dynamic behavior of waste
heat recovery from gas turbine exhaust was
achieved, providing valuable insights into the
transient response of WHR systems and guiding
the optimization of their design and operation
under varying operating conditions.
RESULTS
The dynamic simulation of waste heat recovery
from gas turbine exhaust, focusing on modeling
transient behavior, yielded insightful results
regarding the dynamic response of the WHR
system under varying operating conditions.
Numerical simulations revealed the transient
behavior of key system parameters, including
temperature profiles, heat transfer rates, and
energy conversion efficiency, during load changes,
startup, and shutdown processes. The simulations
provided valuable insights into how the WHR
system responds to transient conditions and
identified potential areas for improvement in
system design and operation.
DISCUSSION
The dynamic simulation results highlighted the
importance of accurately modeling transient
behavior in waste heat recovery systems to
optimize their performance under varying
operating conditions. During load changes, for
example, the simulations showed fluctuations in
temperature profiles and heat transfer rates within
the WHR system, indicating the need for adaptive
control
strategies
to
maintain
optimal
performance. Similarly, during startup and
shutdown processes, transient effects such as
temperature overshoots and heat transfer delays
were observed, underscoring the importance of
proper system initialization and shutdown
procedures to minimize energy losses and
maximize efficiency.
The insights gained from the dynamic simulation
analysis provide valuable guidance for improving
the design and operation of waste heat recovery
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systems. By incorporating transient behavior into
system modeling and control strategies, engineers
can develop more robust and efficient WHR
systems capable of adapting to changing operating
conditions while maximizing energy recovery and
minimizing environmental impact.
CONCLUSION
In conclusion, the dynamic simulation of waste
heat recovery from gas turbine exhaust, with a
focus on modeling transient behavior, offers
valuable insights into the dynamic response of
WHR systems under varying operating conditions.
By accurately capturing transient effects such as
load changes, startup, and shutdown processes, the
simulations
provide
a
comprehensive
understanding of how the WHR system behaves
dynamically and identify opportunities for
optimization.
The findings of this study underscore the
importance of considering transient behavior in
the design and operation of waste heat recovery
systems to maximize energy recovery, improve
efficiency, and reduce environmental impact.
Moving forward, further research is needed to
refine dynamic simulation models, validate their
predictions against experimental data, and develop
advanced control strategies to optimize the
dynamic performance of WHR systems in real-
world applications. Overall, dynamic simulation
represents a powerful tool for advancing the design
and operation of waste heat recovery systems and
promoting sustainable energy use in industrial
processes.
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