Article
Thermodynamics
Mehran Ansari, Vahid Esfahanian, Mohammad Javad Izadi, Hosein Bashi, Alireza Tavakoli, Mohammad Kordi
Summary: This paper develops an object-oriented in-house mean-line code with the ability of hot steam injection calculation for steam turbines. A multi-objective genetic algorithm optimization and a neural network are used to redesign the steam turbine. The results show that hot steam injection can significantly improve both quality and power compared to the baseline.
Article
Thermodynamics
Amir Kafaei, Fahime Salmani, Esmail Lakzian, Wlodzimierz Wroblewski, Mikhail S. Vlaskin, Qinghua Deng
Summary: In order to enhance the efficiency of steam turbines, injecting hot steam between the blades in a 3D manner was studied in this paper. The optimal angle for injection holes was found to be -60 degrees, resulting in reductions of 40% in liquid mass fraction, 22% in condensation loss, and 1% in kinetic energy. The economic cost was calculated at 0.56 ($/hour) with a hot steam injection hole size of 0.07.
INTERNATIONAL JOURNAL OF THERMAL SCIENCES
(2022)
Article
Mechanics
Mohammad Ghodrati, Esmail Lakzian, Heuy Dong Kim
Summary: Injecting hot steam into the cascade flow is a procedure for preventing losses and damages caused by condensation. By utilizing a 3D geometry for steam turbine blades and the TOPSIS optimization method, the best temperature for hot steam injection has been obtained for both constant pressure and constant mass flow rate methods.
Article
Thermodynamics
Mohammad Ghodrati, Esmail Lakzian, Amir Kafaei, Wei Mon Yan, Heuy Dong Kim
Summary: By installing a channel inside the 3D turbine blade to allow hot steam storage and injection, it is possible to reduce wet steam losses in steam turbines and affect other key parameters.
APPLIED THERMAL ENGINEERING
(2023)
Article
Thermodynamics
Amir Kafaei, Esmail Lakzian, Goodarz Ahmadi, Slawomir Dykas
Summary: This study investigates the effect of different hot steam injection hole arrangements on the performance of steam turbines and finds that the in-line no. 1 arrangement is the best design. Excessive kinetic energy loss due to hot steam injection can be prevented by decreasing the injection pressure.
JOURNAL OF THERMAL ANALYSIS AND CALORIMETRY
(2022)
Article
Thermodynamics
Pengfei Hu, Pu Zhao, Qi Li, Tianbo Hou, Shibo Wang, Lihua Cao, Yanhong Wang
Summary: In this paper, the classical homogeneous nucleation theory is deduced and summarized based on the theory of thermodynamic free energy of molecular condensation, and a more accurate modified homogeneous nucleation model is proposed based on the Kantrowitz non-isothermal modified nucleation model. The modified model is validated by calculating the non-equilibrium condensation flow in Moses-Stein nozzle, and the results show good agreement with previous experimental results. The effect of steam expansion rate on nucleation is also investigated, and it is found that increasing inlet steam superheat and decreasing expansion rate can reduce the non-equilibrium condensation flow loss. Additionally, the non-equilibrium condensation flow in a three-dimensional turbine cascade is numerically studied, and the results indicate a decrease in expansion rate, nucleation rate, droplet number, and wetness with the increase of blade height.
Article
Thermodynamics
Hongbing Ding, Yu Zhang, Chunqian Sun, Esmail Lakzian, Chuang Wen, Chao Wang
Summary: This research develops a non-equilibrium condensation model with sliding mesh technology to solve the unsteady condensing flow inside a 3D wet steam stage of a steam turbine. The results quantitatively evaluate the condensation loss and entropy generation considering off-design operation and rough blades, and identify the occurrence of secondary expansion and condensation near the rotor trailing edge.
INTERNATIONAL JOURNAL OF THERMAL SCIENCES
(2022)
Article
Thermodynamics
Mohammad Ghodrati, Esmail Lakzian, Heuy Dong Kim
Summary: In this study, a channel embedded in the turbine blade has been used to solve the problem of water droplets condensation, making hot steam injection and blade surface heating practical. By utilizing surface heating and hot steam injection, the negative effects of droplets on turbine performance can be reduced, while the kinetic energy conversion efficiency is increased.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2023)
Article
Construction & Building Technology
Yu Lei, Shengyu Li, Jun Lu, Ye Xu, Yong Yong, Dingding Xing
Summary: This paper proposes a bi-loop double-evaporator ejection-compression cycle that utilizes low-grade heat and is suitable for the construction industry. The use of the wet steam model in optimizing the ejector geometry significantly reduces errors in entrainment ratio compared to experimental data. The study focuses on critical attributes of wet steam to develop a strategy for enhancing ejector performance and efficiency.
Article
Thermodynamics
Amir Momeni Dolatabadi, Jamshid Moslehi, Mohsen Saffari Pour, Seyed Soheil Mousavi Ajarostaghi, Sebastien Poncet, Muslum Arici
Summary: The study aims to reduce condensing losses of wet steam flow and increase the energy efficiency of steam turbine by injecting Nano-droplets in nucleation zone. The results are validated with experimental data and the SST k-u turbulence model is utilized to simulate the effects of Nano-droplets. Effective energy parameters have been presented, resulting in a significant decrease in condensation losses and improvements in efficient energy and Mach number.
Article
Physics, Multidisciplinary
Bin Yang, Xiaojing Ma, Hailun Zhang, Wenxu Sun, Lei Jia, Haoyuan Xue
Summary: This study investigates the impact of steam superheat on ejector performance and non-equilibrium condensation phenomena using a wet steam model. The simulations demonstrate that increasing primary flow superheat enhances the entrainment ratio, while increasing secondary flow superheat decreases the entrainment ratio. The non-equilibrium condensation starting position shifts backwards and the mass fraction of condensed droplets decreases as primary flow superheat increases.
Article
Thermodynamics
Seyed Ehsan Hosseinizadeh, Erfan Ghamati, Ali Jahangiri, Sahand Majidi, Iman Khazaee, Mohammad Ali Faghih Aliabadi
Summary: Steam turbine plays a vital role in industry as a crucial equipment for energy conversion. However, the non-equilibrium condensation in the steam turbine leads to the formation of tiny droplets, which can reduce efficiency and pose safety risks. This study investigates the use of hot steam injection to control droplet size and liquid mass fraction in steam turbine blades, considering friction and thermal entropy generation. The results show that hot steam injection can significantly reduce condensation loss, erosion rate, and blade inlet flow rate, while increasing generated entropy.
INTERNATIONAL JOURNAL OF THERMAL SCIENCES
(2023)
Article
Thermodynamics
Yiqiao Li, Chao Niu, Shengqiang Shen, Xingsen Mu, Liuyang Zhang
Summary: This study investigated the influence of double choking phenomenon on the performance of a supersonic steam ejector through numerical simulations. It revealed the internal relationship between double choking characteristics and shock waves, as well as the critical choking position and its impact on performance. Additionally, the study found that three-dimensional effects lead to significant differences in both flow field and ejector performance.
APPLIED THERMAL ENGINEERING
(2022)
Article
Thermodynamics
Yiqiao Li, Shengqiang Shen, Chao Niu, Xingsen Mu, Liuyang Zhang
Summary: This paper investigates the effects of variable motive pressures on the shock waves, non-equilibrium condensation, and ejector performance in supersonic steam ejectors. The results reveal the essential connection between the performance and shock waves. It is found that the motive pressure is optimal when the shock wave intensity is the lowest and the shock wave number is the least, and the position of the condensation shock wave moves upstream by 1.2%.
INTERNATIONAL JOURNAL OF THERMAL SCIENCES
(2023)
Article
Thermodynamics
Seyed Ali Hosseini, Esmail Lakzian, Mehdi Nakisa
Summary: Nowadays, it is important to reduce losses and increase the lifetime of industrial equipment. Steam turbines are crucial equipment in power plants but are expensive, so reducing losses and maintenance are crucial. The last stage of the steam turbine faces the issue of two-phase flow, which reduces efficiency and damages turbine blades. To decrease the liquid phase, the use of drainage grooves is proposed. This paper optimizes the drainage groove variables using TOPSIS method and determines the optimal status as location 3, angle 90, width 0.06, and drainage pressure 80 kPa. In this optimized status, condensation loss and erosion rate decreased, while entropy generated and drainage ratios increased.
INTERNATIONAL COMMUNICATIONS IN HEAT AND MASS TRANSFER
(2023)
Article
Engineering, Mechanical
D. Hoseinzade, E. Lakzian, S. Dykas
Summary: By optimizing the trailing edge rotation, the thermodynamic losses and blade erosion caused by wetness in the low-pressure steam turbine can be reduced. The results show that the optimal trailing edge rotation can improve the targeted goals and decrease the erosion rate and condensation losses.
EXPERIMENTAL TECHNIQUES
(2023)
Article
Engineering, Mechanical
E. Behnamtalab, E. Lakzian, S. B. Hosseini
Summary: This paper studies the effect of USBR VI stilling basin geometry on entropy generation and introduces total entropy generation as a design index, comparing the results with flow characteristics and outlet flow. The study shows that the W/D ratio has a significant impact on flow field, entropy generation rate, and total entropy generation.
EXPERIMENTAL TECHNIQUES
(2023)
Article
Engineering, Mechanical
Esmail Lakzian, Shima Yazdani, Bok Jik Lee
Summary: This paper discusses a new flow control method and optimization of two-phase flow, aiming to improve thermodynamic efficiency by reducing droplet radius and wetness fraction.
INTERNATIONAL JOURNAL OF MECHANICAL SCIENCES
(2023)
Article
Thermodynamics
Ahmad Jahani Rahvard, Shahram Karami, Esmail Lakzian
Summary: In this paper, a computational fluid dynamic (CFD) model was used to simulate the dispersion of COVID-19 virus in a conference hall when a patient coughs, and the effect of the position of air conditioning system's supply and return registers was investigated. The simulation results showed that when the inlet registers were located on the longitudinal wall, the virus particles were completely removed from the air after 80 seconds, while in other cases, virus particles still remained.
INTERNATIONAL JOURNAL OF REFRIGERATION
(2023)
Article
Thermodynamics
Amir Momeni Dolatabadi, Mohammad Javad Eghbali, Turcanu Florin-Emilian, Elaheh Mohamadpour, Reza Amini
Summary: This study focuses on wetness loss, condensation loss, erosion rate, and kinetic energy of condensing steam flow in industrial equipment, and investigates the impact of MHD fields on these losses. The findings show that MHD fields play an important role in the nucleation zone and can reduce condensation loss and droplet quantity.
APPLIED THERMAL ENGINEERING
(2023)
Article
Thermodynamics
Mohammad Ghodrati, Esmail Lakzian, Amir Kafaei, Wei Mon Yan, Heuy Dong Kim
Summary: By installing a channel inside the 3D turbine blade to allow hot steam storage and injection, it is possible to reduce wet steam losses in steam turbines and affect other key parameters.
APPLIED THERMAL ENGINEERING
(2023)
Article
Energy & Fuels
Sima Shabani, Miroslaw Majkut, Slawomir Dykas, Krystian Smolka, Esmail Lakzian, Guojie Zhang
Summary: The paper discusses the challenges of numerical modeling of condensing steam flows in steam turbines due to the two-phase nature of the flow and the need to treat steam as a real gas. Two different Eulerian approaches were compared and it was found that the choice of numerical schemes and governing equations can greatly affect the modeling of wet steam flows. The results of the numerical simulations were compared to experimental data and although both codes showed good capabilities in predicting the condensation process, there were some differences in the flow field parameters.
Article
Thermodynamics
Esmail Lakzian, Mostafa Ramezani, Sima Shabani, Fahime Salmani, Miroslaw Majkut, Heuy Dong Kim
Summary: The purpose of this study is to model steam condensing flows through steam turbine blades and find the most suitable condensation model. Through combining five nucleation equations and four droplet growth equations, 20 cases are considered to model the wet steam flow. The proposed case, combining the Hale nucleation equation with the Gyarmathy droplet growth equation, shows the smallest error in the simulation of wet steam flows through steam turbine blades.
INTERNATIONAL JOURNAL OF NUMERICAL METHODS FOR HEAT & FLUID FLOW
(2023)
Article
Thermodynamics
Shahram Karami, Esmail Lakzian, Goodarz Ahmadi
Summary: This study examines the conditions and safety measures for COVID-19 virus transmission in a dental clinic through simulating flow fields and assessing infection risks, effectively reducing the risk of infection for individuals.
INTERNATIONAL JOURNAL OF REFRIGERATION
(2023)
Article
Engineering, Chemical
Daryoush Dadpour, Mohammad Gholizadeh, Esmail Lakzian, Mostafa Delpisheh, Heuy Dong Kim
Summary: Advances in technology have resulted in increased energy consumption and global warming. To address this issue, the optimal use of energy is being promoted in accordance with the Paris agreement. Among the sectors responsible for high energy consumption, air conditioning and refrigeration systems have prompted the implementation of optimization measures. This research focuses on utilizing the waste heat from a 2000 cc engine radiator as an alternative to conventional refrigeration cycles in vehicles. The ejector refrigeration cycle is modeled and optimized using TOPSIS multi-objective optimization method, resulting in reduced power consumption, capital investment cost, and increased COP compared to conventional systems.
JOURNAL OF THE TAIWAN INSTITUTE OF CHEMICAL ENGINEERS
(2023)
Article
Environmental Sciences
Mohammadreza Haghdoost, Esmail Lakzian, Reza Norouzi, John Abraham, SeyedMohsen Sajjadi, Javad Ahadiyan
Summary: This research evaluates the effects of penetration depth, distance from the beginning of the crest width, and inclination angle of the internal cutoff wall on design parameters in an embankment dam. The presence of an internal cutoff wall leads to a significant decline in the phreatic line level. Increasing penetration depth decreases seepage flow, while increasing distance from the crest width and inclination angle increases seepage discharge and hydraulic gradient. An internal cutoff wall with an inclination angle of 45 degrees and penetration depth of 24 m has the best performance at reducing seepage by 49.7%.
MODELING EARTH SYSTEMS AND ENVIRONMENT
(2023)
Article
Thermodynamics
Jalal Salimi, Ali Reza Teymourtash, Mohammad Reza Aghdasi, Esmail Lakzian
Summary: The goal of this study is to find the optimal surface heating technique for a stationary cascade turbine blade in wet steam flow using a genetic algorithm. The research utilizes a numerical method that combines the two-dimensional Navier-Stokes equations with a SSTk-omega turbulence model, and solves nucleation and droplet growth equations using the Eulerian-Eulerian approach. The results show good agreement with established experiments, and it is found that there is an optimum surface heating rate to achieve the best performance of steam turbines.
THERMAL SCIENCE AND ENGINEERING PROGRESS
(2023)
Article
Mechanics
Mohammad Ghodrati, Esmail Lakzian, Heuy Dong Kim
Summary: Injecting hot steam into the cascade flow is a procedure for preventing losses and damages caused by condensation. By utilizing a 3D geometry for steam turbine blades and the TOPSIS optimization method, the best temperature for hot steam injection has been obtained for both constant pressure and constant mass flow rate methods.
Article
Mechanics
Seyed Ali Hosseini, Mehdi Nakisa, Esmail Lakzian
Summary: Nowadays, increasing the efficiency and improving the performance of steam turbines is essential due to their significant role in providing energy. Wet steam flow in the low-pressure stage of steam turbines can result in energy loss, efficiency drop, and erosion/corrosion problems. The research investigates the effect of the drainage groove location on the surface of steam turbine blades. The results indicate that the location of the drainage groove impacts the groove performance and flow pattern, reducing liquid drainage, condensation losses, and erosion rate. The findings contribute to the enhancement of the lifetime, repair and maintenance, and output power of steam power generation facilities.
Article
Engineering, Mechanical
Reza Dolatabadi, Esmail Lakzian, Samaneh Masoumi, Slawomir Dykas, Nader Karimi, Fayssal Benkhaldoun, Mikhail S. Vlaskin
Summary: The design of the rotor stagger angle and operating conditions in the low-pressure stage of the steam turbine can reduce the effects of liquid phase in the wet steam flow, improving turbine efficiency. Simulations and experiments were conducted to determine the optimal rotor stagger angle and outlet pressure, resulting in a significant increase in turbine stage efficiency.
PROCEEDINGS OF THE INSTITUTION OF MECHANICAL ENGINEERS PART C-JOURNAL OF MECHANICAL ENGINEERING SCIENCE
(2023)
