检索结果-南通市图书馆

Optimization of operating conditions in the steam turbine blade cascade using the black-box method

Propulsion and Power Research 2023年第4期12卷 467-485页

作者： Vahid Sadrian Esmail Lakzian Davood Hoseinzade Behrad Haghighi M.M.Rashidi heuy dong kim Center of Computational Energy Department of Mechanical EngineeringHakim Sabzevari UniversitySabzevarIran Department of Mechanical Engineering Andong National UniversityAndongSouth Korea Department of Mechanical Engineering Vali-e-Asr University of RafsanjanRafsanjanIran Institute of Fundamental and Frontier Sciences University of Electronic Science and Technology of ChinaChengdu 610054China Faculty of Science University of JohannesburgPO Box 524Auckland Park 2006South Africa

Water droplets cause corrosion and erosion,condensation loss,and thermal efficiency reduction in low-pressure steam turbines.In this study,multi-objective optimization was carried out using the black-box method through the automatic linking of a genetic algorithm(GA)and a computational fluid dynamics(CFD)code to find the optimal values of two design variables(inlet stagnation temperature and cascade pressure ratio)to reduce wetness in the last stages of turbines.The wet steam flow numerical model was used to calculate the optimization parameters,including wetness fraction rate,mean droplet radius,erosion rate,condensation loss rate,kinetic energy rate,and mass flow rate.Examining the validation results showed a good agreement between the experimental data and the numerical outcomes.According to the optimization results,the inlet stagnation temperature and the cascade pressure ratio were proposed to be 388.67(K)and 0.55(-),respectively.In particular,the suggested optimaltemperature and pressure ratio improved the liquid mass fraction and mean droplet radius by about 32%and 29%,respectively.Also,in the identified optimal operating state,the ratios of erosion,condensation loss,and kinetic energy fell by 76%,32.7%,and 15.85%,respectively,while the mass flow rate ratio rose by 0.68%.

关键词： Black-box optimization Wet steam flow Steam turbine cascade Erosion rate Condensation loss

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Experimental Study on the Inlet Fogging System Using Two-Fluid Nozzles

引用

Journal of Thermal Science 2010年第2期19卷 132-135页

作者： Abhilash Suryan dong Sun kim heuy dong kim School of Mechanical Engineering Andong National University FMTRC Daejoo Machinery Co.

Large-capacity compressors in industrial plants and the compressors in gas turbine engines consume a considerable amount of power.The compression work is a strong function of the ambient air temperature.This increase in compression work presents a significant problem to utilities,generators and power producers when electric demands are high during the hot months.In many petrochemical process industries and gas turbine engines,the increase in compression work curtails plant output,demanding more electric power to drive the system.One way to counter this problem is to directly cool the inlet air.Inlet fogging is a popular means of cooling the inlet air to air compressors.In the present study,experiments have been performed to investigate the suitability of two-fluid nozzle for inlet fogging.Compressed air is used as the driving working gas for two-fluid nozzle and water at ambient conditions is dragged into the high-speed air jet,thus enabling the entrained water to be atomized in a very short distance from the exit of the two-fluid nozzle.The air supply pressure is varied between 2.0 and 5.0 bar and the water flow rate entrained is measured.The flow visualization and temperature and relative humidity measurements are carried out to specify the fogging characteristics of the two-fluid nozzle.

关键词：雾化喷嘴双流体喷雾系统实验燃气涡轮发动机气压缩机水流量测量石油化工过程

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Supersonic Cavity Based Combustion with Kerosene/Hydrogen Fuel

引用

Journal of Thermal Science 2015年第2期24卷 164-172页

作者： Rajarshi Das Jeong Soo kim heuy dong kim Department of Mechanical Engineering Andong National University School of Mechanical Engineering Pukyong National University

A comparative study with kerosene and hydrogen fuel in a model scramjet combustor has been carried out numerically. The effect of fuel-air equivalence ratio on the flow field properties in a cavity based mixing mechanism at a freestream Mach number of 2.08 has been probed. The investigation has been carried out in a two dimensional numerical model where a cavity of length to depth ratio of 2 is mounted on one of the walls of the flow channel. The flow field shock structure is observed to change with the change in fuel-air equivalence ratio. Total pressure loss is observed to depend both on fuel air equivalence ratio and the fuel type. The spread of fuel in the test section shows marked variation with the equivalence ratio. Performance of injector location on the fuel-air mixing is also probed during the course of the investigation.

关键词：氢燃料燃烧室煤油超音速空气混合流场特性发动机模型当量比

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Numerical Simulation of Flow Characteristics in Micro Shock Tubes

引用

Journal of Thermal Science 2015年第3期24卷 246-253页

作者： Guang Zhang Toshiaki Setoguchi heuy dong kim Department of Mechanical Engineering Andong National University Department of Mechanical Engineering Saga University

Recently micro shock tubes have been widely used in many engineering and industrial fields, but the characteristics of unsteady flow are not well known to date in micro shock tubes. Compared to conventional shock tubes with macro scales, flows related to shock waves in micro shock tubes are highly complicated. Stronger viscous and dissipative interactions make shock wave dynamic behaviors significantly different from theoretical predictions. In the present study, a CFD work was applied to the unsteady compressible Navier-Stokes equations which were solved using a fully implicit finite volume scheme. The diaphragm pressure ratio and shock tube diameter were varied to investigate their effects on micro shock tube flows. Different wall boundary conditions were also performed to observe shock wave and contact surface propagation with no slip and slip walls. Detailed flow characteristics at the foot of shock wave and contact surface propagation were known from the present numerical simulations.

关键词：激波管流动数值模拟可压缩Navier-Stokes方程流动特性非定常流有限体积法冲击波工业领域

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

The Effect of Diffuser Angle on the Discharge Coefficient of a Miniature Critical Nozzle

引用

Journal of Thermal Science 2010年第3期19卷 222-227页

作者： Jae Hyung kim heuy dong kim Toshiaki Setoguchi School of Mechanical Engineering Andong National UniversityAndong760-749Korea Department of Mechanical Engineering Saga University1HonjoSagaJapan

Many researches on critical nozzles have been performed to accurately measure the mass flow rate of gas flow,and to standardize the performance as a flow meter.Recently,much interest is being paid on the measurement of very small mass flow rate in industry fields such as MEMS applications.However,the design and performance data of the critical nozzles obtained so far have been applied mainly to the critical nozzles with comparatively large diameters,and the works available on miniature critical nozzles are lacking.In the present study,a computational fluid dynamics method has been applied to investigate the influence of the diffuser angle on discharge coefficient of the miniature critical nozzles.In computations,the throat diameter of critical nozzle is varied from 0.2 mm to 5.0 mm and the diffuser angle is changed from 2 deg to 8 deg.The computational results are validated with some experimental data available.The results show that the present computational results predict appropriately the discharge coefficient of the gas flows through miniature critical nozzles.It is known that the discharge coefficient is considerably influenced by the diffuser angle,as the throat diameter of nozzle becomes small below a certain value.This implies that the miniature critical nozzles should be carefully designed.

关键词：喷嘴直径扩散角微型临界质量流量放电流动性能计算系数

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Study on the Wiping Gas Jet in Continuous Galvanizing Line

引用

Journal of Thermal Science 2011年第3期20卷 242-247页

作者： Yong-Hun Kweon heuy-dong kim POSCO Technical Research Laboratories 699 Gumho-dong GwangyangJeonnam 545-090 Korea School of Mechanical Engineering Andong National UniversityAndong 760-749 Korea

In the continuous hot-dip galvanizing process, the gas-jet wiping is used to control the coating thickness of moving steel strip. The high speed gas-jet discharged from the nozzle slot impinges on the strip, and at this moment, wipes the liquid coating layer dragged by a moving strip. The coating thickness is generally influenced on the flow characteristics of wiping gas-jet such as the impinging pressure distribution, pressure gradient and shear stress distribution on the surface of strip. The flow characteristics of wiping gas-jet mentioned above depends upon considerably both the process operating conditions such as the nozzle pressure, nozzle-to-strip distance and line speed, and the geometry of gas-jet wiping apparatus such as the height of nozzle slot. In the present study, the effect of the geometry of nozzle on the coating thickness is investigated with the help of a computational fluid dynamics method. The height of nozzle slot is varied in the range of 0.6mm to 1.7mm. A finite volume method (FVM) is employed to solve two-dimensional, steady, compressible Navier-Stokes equations. Based upon the results obtained, the effect of the height of nozzle slot in the gas-jet wiping process is discussed in detail. The computational results show that for a given standoff distance between the nozzle to the strip, the effective height of nozzle slot exists in achieving thinner coating thickness.

关键词：气体喷射镀锌生产线 Stokes方程喷嘴压力涂层厚度几何形状计算结果连续热镀锌

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Computational Study of Performance Characteristics for Truncated Conical Aerospike Nozzles

引用

Journal of Thermal Science 2017年第6期26卷 483-489页

作者： Prasanth P Nair Abhilash Suryan heuy dong kim Department of Mechanical Engineering College of Engineering Trivandrum Department of Mechanical Engineering Andong National University

Aerospike nozzles are advanced rocket nozzles that can maintain its aerodynamic efficiency over a wide range of altitudes. It belongs to class of altitude compensating nozzles. A vehicle with an aerospike nozzle uses less fuel at low altitudes due to its altitude adaptability,where most missions have the greatest need for thrust. Aerospike nozzles are better suited to Single Stage to Orbit(SSTO) missions compared to conventional nozzles. In the current study, the flow through 20% and 40% aerospike nozzle is analyzed in detail using computational fluid dynamics technique. Steady state analysis with implicit formulation is carried out. Reynolds averaged Navier-Stokes equations are solved with the Spalart-Allmaras turbulence model. The results are compared with experimental results from previous work. The transition from open wake to closed wake happens in lower Nozzle Pressure Ratio for 20% as compared to 40% aerospike nozzle.

关键词：计算流体动力学塞式喷管性能特性 Stokes方程气动效率海拔高度单级入轨喷管流动

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Study of Spiral Flow Generated through an Annular Slit

引用

Journal of Thermal Science 2005年第2期14卷 97-102页

作者： Tae Hun kim Shigeru MATSUO Toshiaki SETOGUCHI heuy-dong kim Graduate school of Science and Technology Saga University 1Honjo-machiSaga shiSaga 840-8502JapanDepartment of Mechanical Engineering Saga University1Honjo-machiSaga shiSaga 840-8502JapanDepartment of Mechanical Engineering Saga University1Honjo-machiSaga shiSaga 840-8502JapanSchool of Mechanical Engineering College of Natural ScienceAndong National University388Song Cheon DongAndongKyung PookKorea

The effect of pressurized air inlets in the reservoir upstream of the annular slit on characteristics of the axial and tangential velocity components is investigated numerically, and the mechanism of occurrence of spiral nozzle flow is clarified. In simulations, Unified Platform for Aerospace Computational Simulation (UPACS) is used. The governing equations under consideration are the unsteady compressible Navier - Stokes. A second-order finite volume scheme with MUSCL (Roe scheme) is used to discretize the spatial derivatives, and a second order-central difference scheme for the viscous terms, and a MFGS (Matrix Free Gauss Seidel) is employed for time integration. Spalart-Allmaras model was used as a turbulence model. The results obtained are compared with velocity distributions in the experiment measured by the two-component fiber optic laser Doppler velocimeter system. The existence of discrete pressurized air inlets that leads to the occurrence of asymmetrical characteristics is a very important factor for the formation of spiral flow.

关键词：旋转喷嘴流柯恩达效应渐缩喷嘴环形裂缝计算机仿真

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Theoretical and Computational Analyses of LNG Evaporator

引用

Journal of Thermal Science 2017年第2期26卷 132-137页

作者： Palani Kumar Chidambaram Yang Myung Jo heuy dong kim FMTRC Daejoo Machinery Co Ltd Department Mechanical Engineering Andong National University

Theoretical and numerical analysis on the fluid flow and heat transfer inside a LNG evaporator is conducted in this work. Methane is used instead of LNG as the operating fluid. This is because; methane constitutes over 80% of natural gas. The analytical calculations are performed using simple mass and energy balance equations. The analytical calculations are made to assess the pressure and temperature variations in the steam tube. Multiphase numerical simulations are performed by solving the governing equations(basic flow equations of continuity, momentum and energy equations) in a portion of the evaporator domain consisting of a single steam pipe. The flow equations are solved along with equations of species transport. Multiphase modeling is incorporated using VOF method. Liquid methane is the primary phase. It vaporizes into the secondary phase gaseous methane. Steam is another secondary phase which flows through the heating coils. Turbulence is modeled by a two equation turbulence model. Both the theoretical and numerical predictions are seen to match well with each other. Further parametric studies are planned based on the current research.

关键词： LNG 计算能量平衡方程多相流模型甲烷气体蒸汽管道流体流动数值分析

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Supersonic Cavity Flows over Concave and Convex Walls

引用

Journal of Thermal Science 2016年第2期25卷 145-152页

作者： A Ran Ye Rajarshi Das Toshiaki Setoguchi heuy dong kim Department of Mechanical Engineering Andong National University Institute of Ocean Engineering Saga University

Supersonic cavity flows are characterized by compression and expansion waves, shear layer, and oscillations inside the cavity. For decades, investigations into cavity flows have been conducted, mostly with flows at zero pressure gradient entering the cavity in straight walls. Since cavity flows on curved walls exert centrifugal force, the features of these flows are likely to differ from those of straight wall flows. The aim of the present work is to study the flow physics of a cavity that is cut out on a curved wall. Steady and unsteady numerical simulations were carried out for supersonic flow through curved channels over the cavity with L/H = 1. A straight channel flow was also analyzed which serves as the base model. The velocity gradient along the width of the channel was observed to increase with increasing the channel curvature for both concave and convex channels. The pressure on the cavity floor increases with the increase in channel curvature for concave channels and decreases for convex channels. Moreover, unsteady flow characteristics are more dependent on channel curvature under supersonic free stream conditions.

关键词：空腔流动超音速非定常数值模拟弯曲通道压力梯度空腔振荡基准模型速度梯度

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

欢迎您,

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案：

请选择收藏分类：

通借通还

欢迎您,

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：