Effects of working conditions on the performance of an ammonia ejector used in an ocean thermal energy conversion system

Li, Shizhen; Zhai, Xiaoyu; Liu, Yanjun; Liu, Weimin; Wang, Lei; Zhang, Jingzhi

doi:10.1002/cjce.24038

Cited by 3 publications

(2 citation statements)

References 28 publications

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“…For the analysis, the following assumptions have been made along the same lines as Li et al 21 : The ejector is axisymmetric. Basis : The geometry of the considered ejector is symmetric about the axis along the length of the ejector. …”

Section: Methodsmentioning

confidence: 99%

Design optimization of ejectors using ANN and GA

et al. 2022

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Ejectors are devices that are based on the principle of momentum transfer. A primary fluid passes through a nozzle that is usually of converging–diverging cross‐section so that the flow reaches supersonic velocity at the exit. Consequently, a low‐pressure region is created just outside the nozzle exit. This pressure gradient draws out the secondary fluid, into the ejector through the annular space—a phenomenon known as entrainment. This paper attempts to design and optimize an ejector with 1,1‐dichloro‐1‐fluoroethane as the working fluid. The governing equations that accurately predict the behavior of the working fluid, are solved using the finite volume method after the discretization of the flow domain, using ANSYS Fluent. A database is created over 1008 similar computational fluid dynamics simulations by recording the input parameter values and the corresponding output parameter values. It is then used to define a function that can precisely predict the output for an unknown set of input parameters. This is achieved through the implementation of artificial neural networks—a surrogate modeling technique. The accuracy of the model is determined from the coefficient of correlation. The objective function thus obtained is optimized with the help of a genetic algorithm (GA)—a nature‐inspired optimization technique. The optimal design of the ejector for a set of operating conditions is obtained as the output of the GA.

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Section: Methodsmentioning

confidence: 99%

Design optimization of ejectors using ANN and GA

et al. 2022

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“…Ammonia is the most commonly used working fuid in OTEC-ORC due to its large enthalpy diference and easy accessibility [9]. Li et al [10] used an ejector to improve system efciency with ammonia fuid. Hasan and Dincer [6] used the ammonia Rankine cycle for regional cooling, ammonia, and electricity production.…”

Section: Introductionmentioning

confidence: 99%

Performance Improvement of OTEC-ORC and Turbine Based on Binary Zeotropic Working Fluid

Huang

Gao

et al. 2023

International Journal of Chemical Engineering

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In this paper, the composition of binary nonazeotropic working fluids is explored from the perspective of improving OTEC-ORC efficiency, and the turbine is designed to accommodate with the working fluid. It is found that the OTEC-ORC using a R152a/R32 mixture as the working fluid is significantly higher than the OTEC-ORC thermal efficiency and system efficiency of the pure NH3, and the optimal composition of the mixed working fluid R152a/R32 is determined to be 85 : 15 with the thermal efficiency and the system efficiency of 2.8% and 1.7%, respectively, improving by 35.7% and 151.2% compared to the NH3 ORC. According to the determined working fluid, a one-dimensional (1-D) design and CFD simulation analysis simulation are carried out on the turbine. The 1-D calculation results are in good agreement with the three-dimensional (3-D) results. At the design point, the turbine output is 83.84 kW, and the isentropic efficiency is 87.53%. At the off-design point, turbines have better off-design performance, indicating that the designed turbine also has good adaptability.

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A comprehensive exploration of ejector design, operational factors, performance metrics, and practical applications

Kumar,

Yadav,

Kumar

et al. 2023

J Braz. Soc. Mech. Sci. Eng.

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Effects of working conditions on the performance of an ammonia ejector used in an ocean thermal energy conversion system

Abstract: Ocean thermal energy has attracted much attention for its huge potential resources. It's proved that an ocean thermal energy conversion (OTEC) cycle system using ammonia ejectors is beneficial to improve the cycle efficiency.

Cited by 3 publications

References 28 publications

Design optimization of ejectors using ANN and GA

Design optimization of ejectors using ANN and GA

Performance Improvement of OTEC-ORC and Turbine Based on Binary Zeotropic Working Fluid

A comprehensive exploration of ejector design, operational factors, performance metrics, and practical applications

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