Radial Inflow

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Emilie Sauret - One of the best experts on this subject based on the ideXlab platform.

  • meanline analysis and cfd study of a Radial Inflow turbine with vaneless distributor for low temperature organic rankine cycle
    Proceedings of ASME Turbo Expo 2020 Turbomachinery Technical Conference and Exposition GT2020: Volume 9: Oil and Gas Applications; Organic Rankine Cyc, 2020
    Co-Authors: M Deligant, S Braccio, Tommaso Capurso, Francesco Fornarelli, Marco Torresi, Emilie Sauret
    Abstract:

    The Organic Rankine Cycle (ORC) allows the conversion of low-grade heat sources into electricity. Although this technology is not new, the increase in energy demand and the need to reduce CO2 emissions create new opportunities to harvest low grade heat sources such as waste heat. Radial turbines have a simple construction, they are robust and they are not very sensitive to geometry inaccuracies. Most of the Radial Inflow turbines used for ORC application feature a vaned nozzle ensuring the appropriate distribution angle at the rotor inlet. In this work, no nozzle is considered but only the vaneless gap (distributor). This configuration, without any vaned nozzle, is supposed to be more flexible under varying operating conditions with respect to fixed vanes and to maintain a good efficiency at off-design. This paper presents a performance analysis carried out by means of two approaches: a combination of meanline loss models enhanced with real gas fluid properties and 3D CFD computations, taking into account the entire turbomachine including the scroll housing, the vaneless gap, the turbine wheel and the axial discharge pipe. A detailed analysis of the flow field through the turbomachine is carried out, both under design and off design conditions, with a particular focus on the entropy field in order to evaluate the loss distribution between the scroll housing, the vaneless gap and the turbine wheel.

  • uncertainty quantification in high density fluid Radial Inflow turbines for renewable low grade temperature cycles
    Applied Energy, 2019
    Co-Authors: Aihong Zou, Rodney Persky, Jeancamille Chassaing, Emilie Sauret
    Abstract:

    The inclusion of uncertainties in the design of turbines for renewable low-grade temperature power cycles is becoming a crucial aspect in the development of robust and reliable power blocks capable of handling a better range of efficiencies over a wider range of operational conditions. Modelling high-density fluids using existing Equations of State adds complexity to improving the system efficiency and little is known on the effect that the uncertainties of Equations of State parameters may have on the turbine efficiency. The purpose of this paper is to quantify the influence of coupled uncertain variables on the total-to-static efficiency of a Radial-Inflow Organic Rankine Cycle turbine with a high-density fluid R143a in a low-grade temperature renewable power block. To this end, a stochastic solution is obtained by combining a multi-dimensional generalized Polynomial Chaos approach with a full three-dimensional viscous turbulent Computational Fluid Dynamics solver for high-density Radial-Inflow turbines. Both operational conditions (inlet total temperature, rotational speed and mass flow rate) and Equations of State parameters (critical pressure and critical temperature) are investigated, highlighting their importance for turbine efficiency based on the consideration of three Equations of State, namely, Peng-Robinson, Soave-Redlich-Kwong, and HHEOS. This study, which is performed for both nominal and off-design operational conditions, highlights the inlet temperature as the most influential operational uncertain parameters, while the critical pressure is the most sensitive parameter for the three Equations of State tested. More importantly, it demonstrates a higher level of sensitivity of the SRK Equations of State, in particular at off-design operational conditions. This is a crucial aspect to take into account for the robust designs of Organic Rankine Cycle turbines for low-grade temperature renewable power cycles working at various conditions. It is expected that the proposed stochastic approach may consequently positively support the renewable energy sector to develop more robust and viable systems.

  • Loss models for on and off-design performance of Radial Inflow turbomachinery
    Applied Thermal Engineering, 2019
    Co-Authors: Rodney Persky, Emilie Sauret
    Abstract:

    It is critical to accurately predict the performance of Radial Inflow turbomachinery in the preliminary design stages. Preliminary design of Radial Inflow turbomachinery uses basic geometry information and does not have access to detailed blade design. Experimentally derived models using an optimised geometry are widely used to develop a correlation between real world performance and basic design parameters of the turbine. Yet, these correlation models are primarily based on ideal working fluids. Modern turbomachinery systems operate with new complex fluids such as CO2 and R143a which have non-linear compressibility and non-ideal viscosity. Additionally, modern turbomachinery systems are expected to run with reliable performance at off-design conditions. This paper develops a new loss model configuration suitable for the analysis of turbomachinery operating with CO2 and R143a working fluids where off-design performance estimation is critical and temperature fluctuation may be expected. The paper systematically analyses over 1.5 million loss model configurations developed through the enumeration of analytical models for each loss mechanism from within literature. Each loss model configuration is compared against computational simulations of a turbine running at a wide range of off-design conditions. Primary findings of the paper are that loss model configurations must capture the appropriate physics. A loss model configuration must account for slip, as well as interaction between the turbine and immediate downstream components. Furthermore, models that were directly derived from experimental data showed better predictive performance. Specifically, due to the inclusion of appropriate physics and models directly derived from experiments, the proposed loss model within this work showed high accuracy, with a maximum error between the model and CFD of less than 2%. Many performance analysis methods focussed on the on-design performance of turbomachinery alone; the present work extends the application to incorporate more in-depth analysis of the off-design performance of turbomachinery. The paper provides a loss model configuration that is immediately useful for the development of Radial Inflow turbomachinery operating with CO2 and R143a and can be easily adopted to the early cycle design phase to ensure that performance is consistently high.

  • cfd simulation of a supercritical carbon dioxide Radial Inflow turbine comparing the results of using real gas equation of estate and real gas property file
    Applied Mechanics and Materials, 2016
    Co-Authors: Mostafa Odabaee, Emilie Sauret, Kamel Hooman
    Abstract:

    The present study explores CFD analysis of a supercritical carbon dioxide (SCO2) Radial-Inflow turbine generating 100kW from a concentrated solar resource of 560oC with a pressure ratio of 2.2. Two methods of real gas property estimations including real gas equation of estate and real gas property (RGP) file - generating a required table from NIST REFPROP - were used. Comparing the numerical results and time consumption of both methods, it was shown that equation of states could insert a significant error in thermodynamic property prediction. Implementing the RGP table method indicated a very good agreement with NIST REFPROP while it had slightly more computational cost compared to the RGP table method.

  • computational fluid dynamics simulation and turbomachinery code validation of a high pressure ratio Radial Inflow turbine
    Science & Engineering Faculty, 2014
    Co-Authors: Mostafa Odabaee, Emilie Sauret, Kamel Hooman
    Abstract:

    The present study explores reproducing the closest geometry of a high pressure ratio single stage Radial-Inflow turbine applied in the Sundstrans Power Systems T-100 Multipurpose Small Power Unit. The commercial software ANSYS-Vista RTD along with a built in module, BladeGen, is used to conduct a meanline design and create 3D geometry of one flow passage. Carefully examining the proposed design against the geometrical and experimental data, ANSYS-TurboGrid is applied to generate computational mesh. CFD simulations are performed with ANSYS-CFX in which three-dimensional Reynolds-Averaged Navier-Stokes equations are solved subject to appropriate boundary conditions. Results are compared with numerical and experimental data published in the literature in order to generate the exact geometry of the existing turbine and validate the numerical results against the experimental ones.

You-taek Kim - One of the best experts on this subject based on the ideXlab platform.

  • Experiment on Radial Inflow turbines and performance prediction using deep neural network for the organic Rankine cycle
    Applied Thermal Engineering, 2019
    Co-Authors: Jun-seong Kim, Do-yeop Kim, You-taek Kim
    Abstract:

    Abstract The organic Rankine cycle makes it possible to accomplish energy recovery from a low-temperature heat source, which is typically not recovered for economic reasons. As the expander for the organic Rankine cycle, the Radial turbine is easy to manufacture and has advantages in terms of size and efficiency. The Radial turbine design modeler (RTDM), which was developed from in-house code, is a preliminary design program for Radial Inflow turbines and is different from the commercially available program RITAL. In this study, an experiment on Radial Inflow turbines is performed using both RTDM and RITAL. As a result, the output and efficiency of the RTDM and RITAL turbines are 36.04 kW, 80.03% and 35.03 kW, 76.01%, respectively. Experimental results demonstrate that the performance of the RTDM turbine is almost similar to the RITAL turbine. We also perform analysis on performance prediction utilizing a deep neural network with two hidden layers based on the experimental data. As a result, the minimum root mean squared errors of the RTDM turbine and RITAL turbine are estimated to be approximately 1.81 and 1.65, respectively. The deep neural network is able to predict the trends of the experiment for the organic Rankine cycle.

  • Preliminary design and performance analysis of a Radial Inflow turbine for ocean thermal energy conversion
    Renewable Energy, 2017
    Co-Authors: Do-yeop Kim, You-taek Kim
    Abstract:

    Ocean thermal energy conversion is an organic Rankine cycle for generating power using the temperature difference between surface seawater and deep seawater. The potential of ocean thermal energy is significant, and it is an environmentally friendly power system. However, its thermal efficiency is very low due to the low temperature difference between surface seawater and deep seawater. Hence, it is essential to develop a high efficiency turbine in order to improve the thermal efficiency of ocean thermal energy conversion. The precise preliminary design for the high efficiency Radial Inflow turbine requires selection of the appropriate flow and loading coefficients for the target efficiency. A new approach for the appropriate choice of flow and loading coefficients is proposed in this study. The meanline analysis and three-dimensional viscous simulations for the designed turbine are conducted in order to verify the proposed approach in design and off-design conditions. The results demonstrate that the optimum Radial Inflow turbine for the design conditions can be designed through applying the proposed model.

  • Preliminary design and performance analysis of a Radial Inflow turbine for organic Rankine cycles
    Applied Thermal Engineering, 2017
    Co-Authors: Do-yeop Kim, You-taek Kim
    Abstract:

    Abstract Although the turbine among the components of organic Rankine cycle (ORC) has a significant impact on the cycle efficiency, only a handful studies have been conducted so far on the turbine design. The first step in the development of Radial Inflow turbines is the preliminary design, and the rigorous preliminary design can simplify the turbine optimization process. This study proposes a new design method to develop Radial Inflow turbines for ORC. The proposed method does not deal with the ideal gas equation and average state properties. In addition, the performance chart for gas turbines was not used. These improvements are the advantages of the proposed method. Applying the proposed method, we designed a trans-critical Radial Inflow turbine for geothermal power systems and used CFD analysis to evaluate the performance of the designed turbine. For the CFD analysis, grids independent on the turbine output and suitable for y+ criterion were used. And, the numerical models suitable for the flow conditions were also applied. The CFD results showed that the Radial Inflow turbine designed in this study more closely approximated design conditions than one of Sauret and Gu (2014). A turbine performance analysis in off-design conditions was also conducted using CFD. The results showed that the incidence angle to rotor blades as well as RPM had a great impact on the efficiency and output of the turbine. And, these variables could be suitably determined using the proposed design method.

Haisheng Chen - One of the best experts on this subject based on the ideXlab platform.

  • leakage flow characteristic of Radial Inflow turbine adopted in caes system review on progress
    Proceedings of the Institution of Mechanical Engineers Part C: Journal of Mechanical Engineering Science, 2021
    Co-Authors: Xing Wang, Xuehui Zhang, Ziyi Shao, Yangli Zhu, Haisheng Chen
    Abstract:

    Compressed Air Energy Storage (CAES) System is an important power output component of the energy storage technology. Radial Inflow turbine is the main power output device in CAES system, it is oper...

  • Loss analysis of the shrouded Radial-Inflow turbine for compressed air energy storage:
    Proceedings of the Institution of Mechanical Engineers Part A: Journal of Power and Energy, 2020
    Co-Authors: Ziyi Shao, Wang Xing, Zhang Xuehui, Haisheng Chen
    Abstract:

    The shrouded Radial-Inflow turbine is widely employed as a power generation device in the compressed air energy storage (CAES) system. The loss mechanism and off-designed performance of the shroude...

  • flow analysis and performance improvement of a Radial Inflow turbine with back cavity under variable operation condition of compressed air energy storage
    International Journal of Energy Research, 2019
    Co-Authors: Xing Wang, Wen Li, Xuehui Zhang, Haisheng Chen
    Abstract:

    In present study, the effect of back cavity in a Radial Inflow turbine is investigated numerically. The size effect of labyrinth seal clearance is revealed. The performances of Radial turbine with back cavity at different total expansion ratio are also investigated. Results illustrate that the clearance variation of original labyrinth seal in back cavity has limited effect on the leakage flow and the isentropic efficiency. The existence of back cavity reduces the isentropic efficiency at every total expansion ratio, and a maximum isentropic efficiency reduction of 1.5% is obtained when total expansion ratio is 2.89. To control the rotor‐back cavity coupling flow loss, a “rotor‐back cavity seal” is also proposed, and the isentropic efficiency of Radial turbine is significantly improved at different total expansion ratio.

  • effect of blade tip leakage flow on erosion of a Radial Inflow turbine for compressed air energy storage system
    Energy, 2019
    Co-Authors: Xing Wang, Xuehui Zhang, Xinjing Zhang, Yangli Zhu, Haisheng Chen
    Abstract:

    The erosion caused by sand particles significantly influences the safety of Radial Inflow turbine in Compressed Air Energy Storage (CAES) system which operated in desert area. In present study, effects of tip leakage flow on erosion of a CAES Radial Inflow turbine are investigated at different tip clearances and total pressure ratios. A CFD model coupling Tabakoff and Grant erosion model is utilized for the analysis. Results illustrate that the trailing edge of stator, the leading edge of rotor blades, the shroud and hub surfaces near inlet of rotor cause more severe erosion at each tip clearance. Therefore, wear-resistant coating should be adopted. The severe erosion can also be found at blade tip of rotor. However, it is gradually suppressed with the increase of tip clearance. With the increase of total pressure ratio, the region with higher erosion rate on the shroud of rotor gradually extends to downstream. However, the erosion rate at leading edge of rotor blades is decreased obviously. In conclusion, the erosion effect can be alleviated remarkably when the tip clearance size is of 2% and total pressure ratio is more than 1.84, while the isentropic efficiency is almost kept the same.

  • Efficiency improvement of a CAES low aspect ratio Radial Inflow turbine by NACA blade profile
    Renewable Energy, 2019
    Co-Authors: Wang Xing, Zhang Xuehui, Zhu Yangli, Zhitao Zuo, Haisheng Chen
    Abstract:

    Compressed Air Energy Storage (CAES) System is a significant technology for renewable energy utilization. As a power generation device in the system, the blade of Radial Inflow turbine has a lower aspect ratio and tip leakage loss is larger. A novel blade profile based on NACA standard airfoil is proposed and optimized by orthogonal design coupling Computational Fluid Dynamic (CFD) model. The effect of NACA-based profile parameters on isentropic efficiency is obtained and the tip leakage flow loss mechanism is revealed. The applicability of blade with optimal NACA-based profile is investigated under off-design operation and non-uniformity inlet conditions. Results indicate that the optimal NACA-based profile has larger leading edge inscribed circle radius and smaller thickness at trail part of blade which reduces the tip leakage flow velocity near trailing edge and weakens the mixing of the leakage flow and mainstream. As a result, the efficiency of the Radial Inflow turbine can be increased by 1.26%, 1.20% and 1.99% when the tip clearance are 2%, 4%, and 8%, respectively. The blade with optimal NACA-based profile also increases the efficiency of the Radial Inflow turbine at different pressure ratios and inlet attack angles and satisfies the deformation and structure strength requirement.

Jiangfeng Wang - One of the best experts on this subject based on the ideXlab platform.

  • preliminary design and cfd analysis of a Radial Inflow turbine and the turbine seal for an organic rankine cycle using zeotropic mixture
    Energy Conversion and Management, 2020
    Co-Authors: Jiaxi Xia, Jiangfeng Wang, Kehan Zhou, Yumin Guo, Juwei Lou, Yiping Dai
    Abstract:

    Abstract Zeotropic mixtures exhibit great potential for further investigation of organic Rankine cycle (ORC) in the field of low temperature heat utilization because of the characteristics of varying temperature evaporation in two-phase region. However, few studies are contributed to the design of zeotropic mixture turbine and turbine seal. In this paper, the system optimization of ORC by means of genetic algorithm is conducted for different mixtures to obtain the optimal mixture working fluid and initial design parameters of turbine. The thermal design of the mixture ORC Radial Inflow turbine is carried out, and the CFD simulation is performed to investigate the three-dimensional flow characteristic of the designed turbine. Meanwhile, the helical groove seal of the turbine shaft is designed and analyzed through CFD method. Results show that the mixture ORC Radial Inflow turbine is well designed with an isentropic efficiency of 83.71%, and CFD results basically match with the thermal design results. What’s more, the CFD simulation result for the differential pressure of the helical groove seal has an only −5.83% deviation compared with the designed one, and the helical groove seal is well designed with desirable sealing performance.

  • design and performance analysis of a supercritical co2 Radial Inflow turbine
    Applied Thermal Engineering, 2020
    Co-Authors: Kehan Zhou, Jiangfeng Wang, Pan Zhao
    Abstract:

    Abstract Due to the high efficiency and compactness, the supercritical carbon dioxide (S-CO2) Brayton cycle recently emerged as a promising power cycle for the power plant economics. The turbine is the key power unit of the cycle, but relevant investigations are still lacking. In this paper, the design study of an S-CO2 Radial Inflow turbine based on system optimization is conducted. The CFD simulation of the turbine under design and off-design conditions is performed, and tip clearance analysis is conducted to evaluate the turbine performance. The properties of CO2 in the CFD analysis are calculated using the NIST database. Results show that the power output and total-to-static efficiency of the turbine are 1.16 MW and 85.36%, respectively. The largest deviation of design results and simulation results under the nominal condition is 3.73%, indicating that the design model is reliable. Numerical simulations reveal that the turbine maintains great performance at design and off-design conditions. Furthermore, tip clearance analysis shows that a 6% increase of tip clearance results in a 3.84% reduction of turbine efficiency and a 4.16% reduction of turbine power output.

  • Three-dimensional performance analysis of a Radial-Inflow turbine for an organic Rankine cycle driven by low grade heat source
    Energy Conversion and Management, 2018
    Co-Authors: Jiangfeng Wang, Hongyang Wang
    Abstract:

    Abstract Turbine is one of the key components in organic Rankine cycle, and its aerodynamic performance and geometric dimension affect the performance of the system directly. This paper presents the one-dimensional design and three-dimensional CFD analysis for an ORC Radial-Inflow turbine based on the parameter optimization of the system under low grade heat source conditions. Real Gas Property (RGP) file is encoded by using the NIST REFPROP database to guarantee the prediction accuracy of the working fluid properties. The results comparison between the one-dimensional design and the three-dimensional CFD simulation is carried out. What’s more, the addition of splitter blade to the rotor passage is considered to optimize the ORC Radial-Inflow turbine. It is concluded that the three-dimension CFD results are in good agreement with the one-dimensional analysis. And the addition of splitter blade is benefit to improve the performance of the ORC Radial-Inflow turbine.

  • off design performance comparative analysis between basic and parallel dual pressure organic rankine cycles using Radial Inflow turbines
    Applied Thermal Engineering, 2018
    Co-Authors: Yang Du, Dongshuai Hu, Yi Yang, Jiangfeng Wang
    Abstract:

    Abstract This paper compares off-design performances of the basic organic Rankine cycle (ORC) and the parallel dual-pressure organic Rankine cycle (PDORC) for low temperature hot water. Off-design models of the basic ORC and the PDORC are established based on specially designed plate heat exchangers and Radial Inflow turbines. The particle swarm optimization (PSO) algorithm is applied to obtain optimal operating parameters. The sliding pressure operation is adopted for different conditions in terms of corresponding hot water parameters and saturated condensing temperature. The results indicate that the efficiency of the low-pressure Radial turbine is more strongly affected by the hot water mass flow rate ratio than that of the high-pressure Radial turbine does in the PDORC. Radial Inflow turbine efficiencies of the basic ORC and the PDORC are more strongly influenced by the saturated condensing temperature than the hot water inlet temperature. The ratio of the high-pressure subcycle net power to the low-pressure subcycle net power in the PDORC decreases obviously with the increase of the hot water mass flow rate ratio or the decrease of the saturated condensing temperature. The ratio of the PDORC net power to the basic ORC net power decreases to the minimum before increasing with the increase of the hot water mass flow rate ratio, while this net power ratio decreases with the increase of the hot water inlet temperature or the decrease of the saturated condensing temperature.

Kiyarash Rahbar - One of the best experts on this subject based on the ideXlab platform.

  • design and manufacturing a small scale Radial Inflow turbine for clean organic rankine power system
    Journal of Cleaner Production, 2020
    Co-Authors: Raya Aldadah, Kiyarash Rahbar, Ayad Al Jubori, Fadhel Noraldeen Almousawi, Saad Mahmoud
    Abstract:

    Abstract With growing on the energy demand and availability of the low-grade temperature heat source, the organic Rankine cycle as a power system can be efficiently utilized to generate electricity. The turbine design and its performance have the main impact on determining the system power and overall system efficiency. Therefore, design a small-scale organic Rankine system requires the development of an appropriate turbine. To achieve this aim, this work offers an innovative complete design method to develop a Radial-Inflow turbine for small-scale organic Rankine cycle power applications, which includes a preliminary design (i.e. one-dimensional design calculation phase) and a three-dimensional flow analysis using the computational fluid dynamic technique. A thermodynamic analysis of the organic Rankine cycle was integrated with the design methodology. Where the three-dimensional geometry model was built based on the thermodynamic and aerodynamic design, and then was imported into the ANSYS-CFX software to conduct viscous numerical simulations. The optimum design of the Radial-Inflow turbine was manufactured using a three-dimensional printing (pioneering) technique, and the experimental testing was conducted at off-design points to validate the turbine design. The evaluation of the turbine’s performance (efficiency and power) was presented under design and off-design points in terms of rotational speeds, expansion ratios, and inlet temperatures with five different organic fluids. The turbine numerical results showed that R600 as a working fluid has a higher predicted turbine efficiency of 78.32% and power of 4.8 kW with cycle thermal efficiency of 9.15% compared with 8.045% for R245fa. Depending on the experimental results at off-design points, the highest cycle thermal efficiency of 4.25% with a turbine efficiency of 45.22% was achieved. These results assured the precision of the proposed PD methodology at off-design points in making performance maps of the turbine.

  • development and experimental study of a small scale compressed air Radial Inflow turbine for distributed power generation
    Applied Thermal Engineering, 2017
    Co-Authors: Kiyarash Rahbar, Raya Aldadah, Saad Mahmoud, Nima Moazami, Seyed Mirhadizadeh
    Abstract:

    Abstract With ever increasing demand on energy, disturbed power generation utilizing efficient technologies such as compressed air energy storage (CAES) and organic Rankine cycle (ORC) are receiving growing attention. Expander for such systems is a key component and its performance has substantial effects on overall system efficiency. This study addresses such component by proposing an effective and comprehensive methodology for developing a small-scale Radial Inflow turbine (RIT). The methodology consists of 1-D modelling, 3-D aerodynamic investigation and structural analysis, manufacturing with pioneering technique and experimental testing for validation. The proposed 1-D modelling was very effective in determining the primary geometry and performance of turbine based on parametric studies of turbine input design variables. However with CFD analysis, it was shown that more efficient turbine geometry can be achieved that not only provides more realistic turbine performance by capturing the 3-D fluid flow behaviour but also improves turbine efficiency with the aid of parametric studies of turbine geometry parameters. Turbine efficiency was improved from 81.3% obtained from 1-D modelling to 84.5% obtained by CFD. Accuracy of the CFD model was assessed by conducting experiments on the RIT manufactured with stereolithography technique. The CFD model can predict turbine efficiency and power with accuracy of ±16% and ±13% respectively for a wide range of tested operating conditions. Such results highlights the effectiveness of the proposed methodology and the CFD model can be used as benchmarking model for analyses of small-scale RITs. Besides, it was shown that for such applications, the novel manufacturing technique and employed material are very effective for producing prototypes that assist design decisions and validation of CFD model with reasonable accuracy at reasonable cost and in timely manner.

  • modelling and optimization of organic rankine cycle based on a small scale Radial Inflow turbine
    Energy Conversion and Management, 2015
    Co-Authors: Kiyarash Rahbar, Nima Moazami
    Abstract:

    Abstract In most of the organic Rankine cycle (ORC) studies, constant expander efficiency is considered for a wide range of cycle operating conditions and for various working fluids. This study presents an optimized modelling approach for the ORC based on Radial Inflow turbine, where the constant expander efficiency is replaced by dynamic efficiency that is unique for each set of cycle operating conditions and working fluid properties. Considering the size and performance of the ORC, the model was used to identify the key input variables that have significant effects on the turbine overall size and the cycle net electric power output. These parameters were then included in the optimization process using the DIRECT algorithm to maximize the ratio of cycle net electric power output to the turbine overall size (objective function) for six organic fluids. Results showed that, dynamic efficiency approach predicted considerable differences in the turbine efficiencies of various working fluids. The maximum difference of 6.13% between the turbine efficiencies of R245fa and isobutane was predicted. Also the optimization results showed that, the maximum objective function of 0.5748 kW/mm was achieved by isobutane with the cycle net electric power output and the turbine overall size of 90.3 kW and 157.2 mm respectively. Such results are better than the other studies and highlight the potential of the optimization technique to further improve the performance and reduce the size of the ORC based on small-scale Radial turbines.