scholarly journals Cavitating Flow Suppression in the Draft Tube of a Cryogenic Turbine Expander through Runner Optimization

Processes ◽  
2020 ◽  
Vol 8 (3) ◽  
pp. 270
Author(s):  
Ning Huang ◽  
Zhenlin Li ◽  
Baoshan Zhu
Keyword(s):  
Natural Gas ◽  
Optimization Design ◽  
Draft Tube ◽  
Liquefied Natural Gas ◽  
Design Parameters ◽  
Surface Model ◽  
Blade Loading ◽  
Hydraulic Machinery ◽  
Cavitation Phenomenon ◽  
The Relationship

The application of a cryogenic liquefied natural gas expander can reduce the production of flash steam and improve the efficiency of natural gas liquefaction. Like traditional hydraulic machinery, cavitation will occur during the operation of a liquefied natural gas expander, in particular, there is a strong vortex flow in the draft tube, and the cavitation phenomenon is serious. In this paper, the energy loss coefficient of the draft tube is used to describe the cavitation flow in the draft tube, and the goal of reducing the cavitation in the draft tube is achieved through the optimization design of the runner. Different runner models within the range of design parameters were obtained using the Latin hypercube test, and the relationship between design parameters and objective functions is constructed by a second-order response surface model. Finally, the optimized runners were obtained using a genetic algorithm. The effects of blade loading distribution and blade lean angles on the cavitation in the draft tube were studied. According to the optimization results, the blade loading distribution and blade lean angles are recommended in the end.

Multi-Objective Shape Optimization Design for Liquefied Natural Gas Cryogenic Helical Corrugated Steel Pipe

2017 ◽  
Vol 139 (5) ◽  
Author(s):  
Zhixun Yang ◽  
Jun Yan ◽  
Jinlong Chen ◽  
Qingzhen Lu ◽  
Qianjin Yue
Keyword(s):  
Natural Gas ◽  
Optimization Design ◽  
Rbf Neural Network ◽  
Liquefied Natural Gas ◽  
Steel Pipe ◽  
Structural Deformation ◽  
Design Parameters ◽  
Nsga Ii ◽  
Multi Objective ◽  
Operation Conditions

Recently, the flexible cryogenic hose has been preferred as an alternative to exploit offshore liquefied natural gas (LNG), in which helical corrugated steel pipe is the crucial component with C-shaped corrugation. Parametric finite element models of the LNG cryogenic helical corrugated pipe are established using a three-dimensional shell element in this paper. Considering the nonlinearity of cryogenic material and large geometric structural deformation, mechanical behaviors are simulated under axial tension, bending, and internal pressure loads. In addition, design parameters are determined to optimize the shape of flexible cryogenic hose structures through sectional dimension analysis, and sensitivity analysis is performed with changing geometric parameters. A multi-objective optimization to minimize stiffness and stress is formulated under operation conditions. Full factorial experiment and radial basis function (RBF) neural network are applied to establish the approximated model for structure analysis. The set of Pareto optimal solutions and value range of parameters are obtained through nondominated sorting genetic algorithm II (NSGA-II) under manufacturing and stiffness constraints, thereby providing a feasible optimal approach for the structural design of LNG cryogenic corrugated hose.

A Study of Optimization of Blade Section Shape for a Steam Turbine

2005 ◽  
Author(s):  
Kyung-Nam Chung ◽  
Yang-Ik Kim ◽  
Ju-Heon Sung ◽  
In-Ho Chung ◽  
Sang-Hoon Shin
Keyword(s):  
Turbine Blade ◽  
Optimization Design ◽  
Design Method ◽  
Turbine Blades ◽  
Design Parameters ◽  
Surface Model ◽  
Impulse Turbine ◽  
Object Function ◽  
Section Shape ◽  
Blade Section

In this study, an optimization design method is established for a rotor blade of a Curtis turbine. Bezier curve is generally used to define the profile of turbine blades. However, this curve is not proper to a supersonic impulse turbine. Section shape of a supersonic turbine blade is composed of straight lines and circular arcs. That is, it has several constraints to define the section shape. Thus, in this study, a blade design method is developed by using B-spline curve in which local control is possible. The turbine blade section has been changed by varying three design parameters of exit blade angle, stagger angle and maximum camber. Then flow analyses have been carried out for the sections. Lift-drag ratio of the blade section is used as the object function, and it is maximized in the optimization. Second-order response surface model is employed to express the object function as a function of design parameters. Central composite design method is used to reduce the number of design points. Then, an evolution strategy is employed to obtain the optimized section of the Curtis turbine blade.

Multiobjective Optimization Design of a Pump–Turbine Impeller Based on an Inverse Design Using a Combination Optimization Strategy

2013 ◽  
Vol 136 (1) ◽  
Author(s):  
Wei Yang ◽  
Ruofu Xiao
Keyword(s):  
Response Surface ◽  
Optimization Design ◽  
Design Method ◽  
Inverse Design ◽  
Design Parameters ◽  
Surface Model ◽  
Optimization Strategy ◽  
Pump Turbine ◽  
Combination Optimization ◽  
Final Design

This paper presents an automatic multiobjective hydrodynamic optimization strategy for pump–turbine impellers. In the strategy, the blade shape is parameterized based on the blade loading distribution using an inverse design method. An efficient response surface model relating the design parameters and the objective functions is obtained. Then, a multiobjective evolutionary algorithm is applied to the response surface functions to find a Pareto front for the final trade-off selection. The optimization strategy was used to redesign a scaled pump–turbine. Model tests were conducted to validate the final design and confirm the validity of the design strategy.

Utilization of the Cold by LNG Vaporization With Closed-Cycle Gas Turbine

1980 ◽  
Vol 102 (2) ◽  
pp. 225-230 ◽  
Author(s):  
G. Krey
Keyword(s):  
Natural Gas ◽  
Gas Turbine ◽  
Optimization Design ◽  
High Efficiency ◽  
Electrical Energy ◽  
Liquefied Natural Gas ◽  
Partial Recovery ◽  
Closed Cycle ◽  
Save Energy ◽  
Very High

In the course of the world-wide efforts to save energy, the utilization of cold in connection with the regasification of liquefied natural gas gains more and more importance. The aim is the partial recovery of the energy consumed in liquefaction. There are particular advantages when using the closed-cycle gas turbine, in which the exergy of the liquefied natural gas is transformed to electrical energy with a very high efficiency. The paper deals with the optimization, design, and operational behavior of such a plant.

Application of biharmonic equation in impeller profile optimization design of an aero-centrifugal pump

2019 ◽  
Vol 36 (5) ◽  
pp. 1764-1795 ◽  
Author(s):  
Xianwei Liu ◽  
Huacong Li ◽  
Xinxing Shi ◽  
Jiangfeng Fu
Keyword(s):  
Centrifugal Pump ◽  
Surrogate Model ◽  
Biharmonic Equation ◽  
Optimization Design ◽  
Design Parameters ◽  
Surface Model ◽  
Hydraulic Efficiency ◽  
Blade Profile ◽  
Content Type ◽  
Profile Optimization

Purpose The purpose of this paper is to improve the hydraulic efficiency without changing the overall dimension. The blade profile optimization design of the aero-centrifugal pump based on the biharmonic equation surrogate model has been studied. Design/methodology/approach First of all, Bezier curves and linear function are used to control the annular angle distribution and the stacking angle of blade profile under the MATLAB platform. Grid independence analysis has been studied to find the finest mesh scheme. After the precision comparison of test data and computation fluid dynamics 15 sets of design parameters are carried out as the boundary condition of the biharmonic equation. The efficiency surrogate model of the biharmonic equation is constructed via iteratively solving of a discrete difference equation. The other two surrogate models of response surface model (RSM) and radial basis function neural network surrogate model (RBFNNSM) are compared with the biharmonic equation surrogate model by the standard of modified complex correlation coefficient R2 and root mean square deviation (RSME). Finally, the artificial fish swarm algorithm has been used to find the global optimal design parameters with the objective function of highest efficiency. Findings The results show that the design parameters code conversion method can reduce the number of optimization parameters from five to three, makes the design space become a cube, and compared with RSM and RBFNNSM, the biharmonic equation surrogate model has higher precision with R2 is 0.8958, RSME is 0.1382. The final optimum result of AFSA is at the point of [1 −1 −1]. The internal flow field analysis shows that after optimization the outlet relative velocity becomes more uniform and the wake effect has been significantly decreased. The hydraulic efficiency of the optimized pump is about 59.45 per cent increasing 5.4 per cent compared with a prototype pump. Originality/value This study developed a new method to optimize the design parameters of aero-centrifugal pump impeller based on biharmonic equation surrogate model, which had a good agreement with experimental values within just 15 sets of the original design. The optimization results shows that the method can improve the hydraulic efficiency significantly.

Numerical Simulation of Heat Transfer of Liquefied Natural Gas in Horizontal Circular Tubes under Supercritical Pressure

2014 ◽  
Vol 960-961 ◽  
pp. 438-441 ◽  
Author(s):  
Hai Yu Meng ◽  
Shu Zhong Wang ◽  
Lu Zhou ◽  
Zhi Qiang Wu ◽  
Jun Zhao ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Numerical Simulation ◽  
Pressure Drop ◽  
Natural Gas ◽  
Numerical Simulations ◽  
Supercritical Pressure ◽  
Liquefied Natural Gas ◽  
Design Parameters ◽  
Circular Tubes ◽  
Submerged Combustion

The submerged combustion vaporizer (SCV) is a kind of equipment used for liquefied natural gas (LNG) vaporization. In order to get insights into the heat transfer of supercritical LNG, numerical simulations were carried out in this paper for investigating heat transfer of LNG in horizontal circular tubes under supercritical pressure. Numerical results showed that LNG temperature at the outlet under the design parameters was 276 K which met the demands of application. The velocity of LNG at the outlet was 12 m/s, and the pressure drop along the ducts was 120 kPa.

Application, Design and Operation Considerations for Brazed Aluminum Heat Exchangers in Liquefied Natural Gas Service

2008 ◽  
Author(s):  
D. Douglas Miller ◽  
Joe A. Belling ◽  
Jane C. Tettambel
Keyword(s):  
Natural Gas ◽  
Heat Exchangers ◽  
Mechanical Design ◽  
Liquefied Natural Gas ◽  
Design Parameters ◽  
Successful Operation ◽  
Design Considerations ◽  
Operational Design ◽  
Design Characteristics ◽  
Lng Liquefaction

Brazed Aluminum Heat Exchangers (BAHX) are commonly used for heat transfer equipment in liquefied natural gas (LNG) services. Specific operational design parameters as well as mechanical design characteristics are critical to consider in the construction and ultimately for the operation of the unit in order to ensure a safe design and successful operation for the facility. The growth and demand for natural gas has been extensive in recent years as clean burning fuels have become more of a priority than coal plants. Due to limited natural gas supplies, many LNG facilities have been considered as a means to provide and meet the consumers’ needs for natural gas. These LNG facilities such as LNG import receiving terminals or LNG Liquefaction Plants have a need for handling cryogenic materials. In these LNG applications, BAHX are an ideal fit for this use and have many advantages as a result of being able to be designed for minimal approach temperatures as well as lower log mean temperature differences (LMTD) than other exchanger types. These parameters are key to the plant’s refrigeration and overall energy loads. Discussed and detailed in this paper will be various uses and applications for BAHX along with design considerations for their use. Details regarding materials of construction, maintenance, and other mechanical aspects will be presented that lead to a safe and reliable means for transferring heat.

Sign in / Sign up

Export Citation Format

Share Document