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Xu Han, Zhonghe Han, Wei Zeng, Peng Li and Jiangbo Qian
The purpose of this paper is to study the condensation flow of wet steam in the last stage of a steam turbine and to obtain the distribution of condensation parameters such as…
Abstract
Purpose
The purpose of this paper is to study the condensation flow of wet steam in the last stage of a steam turbine and to obtain the distribution of condensation parameters such as nucleation rate, Mach number and wetness.
Design/methodology/approach
Because of the sensitivity of the condensation parameter distribution, a double fluid numerical model and a realizable k-ε-kd turbulence model were applied in this study, and the numerical solution for the non-equilibrium condensation flow is provided.
Findings
The simulation results are consistent with the experimental results of the Bakhtar test. The calculation results indicate that the degree of departure from saturation has a significant impact on the wet steam transonic condensation flow. When the inlet steam deviates from the saturation state, shock wave interference and vortex mixing also have a great influence on the distribution of water droplets.
Originality/value
The research results can provide reference for steam turbine wetness losses evaluation and flow passage structure optimization design.
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Xu Han, Wei Zeng and Zhonghe Han
The purpose of this study is to improved the efficiency of condensing steam turbines by legitimately reforming the flow structure. It is of great significance to study the…
Abstract
Purpose
The purpose of this study is to improved the efficiency of condensing steam turbines by legitimately reforming the flow structure. It is of great significance to study the condensation flow characteristics of wet steam for optimizing the operation of condensing steam turbines.
Design/methodology/approach
A two-fluid model was used to study the wet steam flow in a stator cascade. The effects of the inlet temperature and pressure drop on the cascade performance were analyzed. On this basis, endwall protrusion models were set up at varied axial position on the pressure surface to evaluate the wetness control and loss under different design conditions for cascade optimization.
Findings
The analysis indicates that increasing the inlet temperature or decreasing the pressure drop can effectively control the steam wetness but increase the droplet radius. The increasing inlet temperature can delay the condensation and alleviate the deterioration of the aerodynamic performance of cascades. The non-axisymmetric endwall can significantly affect the distribution of steam parameters below its height and slightly reduce the droplet radius. Compared with the original stator cascade, the optimum design conditions reduce the steam wetness by 8.07 per cent and the total pressure loss by 6.91 per cent below a 20 per cent blade height.
Originality/value
These research results can serve as a reference for condensing steam turbine wetness losses evaluation and flow passage optimization design.
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Xu Han, Xiangyu Liu, Yunyun Yuan and Zhonghe Han
The flow state of wet steam will affect the thermodynamic and aerodynamic characteristics of steam turbine. The purpose of this study is to effectively control the wetness losses…
Abstract
Purpose
The flow state of wet steam will affect the thermodynamic and aerodynamic characteristics of steam turbine. The purpose of this study is to effectively control the wetness losses caused by wet steam condensation, and hence a cascade of 600 MW steam turbine was taken as the research object.
Design/methodology/approach
The influence of blade surface roughness on the condensation characteristics was analyzed, and the dehumidification mechanism and wetness control effect were obtained.
Findings
With the increase of blade surface roughness, the peak nucleation rate decreases gradually. According to the Mach number distribution on the blade surface, there is a sensitive region for the influence of roughness on the aerodynamic performance of cascade. The sensitive region of nucleation rate roughness should be between 50 and 150 µm.
Originality/value
The increase of blade surface roughness will increase the dynamic loss in cascade, but it can reduce the thermodynamic loss caused by condensation to a certain extent.
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Xia Sun, Jianben Xu, Caili Yu and Faai Zhang
The purpose of this paper is to synthesize a polyacrylate-based dispersant with a determined target molecular weight for oily systems and to determine the optimal dispersant level…
Abstract
Purpose
The purpose of this paper is to synthesize a polyacrylate-based dispersant with a determined target molecular weight for oily systems and to determine the optimal dispersant level and monomer ratio of the dispersant.
Design/methodology/approach
The dispersant was synthesized by conventional radical polymerization using methacrylic acid, butyl acrylate and dimethylamino ethyl methacrylate as the monomer. It was characterized by Fourier transform infrared spectroscopy, nuclear magnetic hydrogen spectroscopy, gel permeation chromatography and thermogravimetric analysis. The dispersant was used to disperse TiO2, and the performance of the dispersant was evaluated by measuring the viscosity, particle size and dispersive force of the slurry.
Findings
The dispersant exhibited high thermal stability and was successfully anchored to the surface of the TiO2 pigment. When used to disperse a TiO2 slurry, it effectively made the TiO2 slurry more fluid, indicating its strong viscosity-reducing properties. The viscosity, particle sizes and dispersion capabilities of the TiO2 slurry were found to vary depending on the contents and monomer ratios of the dispersant.
Research limitations/implications
P(MAA-BA-DM) dispersant increases the wettability of TiO2 only in oily solvents but not in aqueous solvents.
Practical implications
P(MAA-BA-DM) dispersant makes it easier to disperse TiO2 pigments in oily solvents, increasing the amount of pigment in the solvent and making the preparation of highly pigmented pastes easier.
Originality/value
A dispersant containing suitable carboxyl and tertiary amine groups was initially synthesized to disperse TiO2 in an oily system. The findings are anticipated to be used in the formulation of pigment concentrates, industrial coatings and other solvent-based coatings.
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The purpose of this study is to explore how nationalistic appeals may affect consumers’ perception and purchasing of targeted brands. Qualitative historical data from old China…
Abstract
Purpose
The purpose of this study is to explore how nationalistic appeals may affect consumers’ perception and purchasing of targeted brands. Qualitative historical data from old China (1900–1949) reveal that social movement groups can adopt nationalistic appeals assisted by meaning framing – defined as a creative interpretation of symbols, designs, behaviors, social events and cultural identities to serve social and political goals – to shape consumers’ attitudes toward foreign brands. After examining the mechanisms and processes underlying consumer boycotts from 1900 to 1949, the responsive strategies of affected foreign companies are illustrated.
Design/methodology/approach
Critical historical research method is applied to historical data and historical “traces” from China’s corporate documents, memoirs, posters, advertisements, newspapers and secondhand sources documenting Chinese boycotts from 1900 to 1949.
Findings
Consumers may pursue interests beyond economic interests. Nationalistic appeals can mobilize consumer boycotts against foreign brands that were perceived to support or relate to targeted countries. Political framing of certain events shapes consumers’ perceptions and concomitant brand choices.
Research limitations/implications
Although differences between historical and current contexts may require tailoring past marketing strategies to current conditions, past strategies can inform current and future strategies.
Practical implications
Strategies adopted by foreign companies in old China (1900–1949) can help contemporary companies design effective marketing strategies for a hostile marketplace infused with nationalistic appeals and competing interests.
Social implications
Although local companies can adopt economic or political nationalism to realize their economic goals, it represents a double-edged sword that can harm national brands.
Originality/value
A historical analysis of nationalistic business appeals in pre-1949 China can inform the counterstrategies modern companies adopt to overcome consumer boycotts.
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Wing Him Yeung and Camillo Lento
The purpose of this paper is to investigate the relationship between corporate governance and earnings opacity in China.
Abstract
Purpose
The purpose of this paper is to investigate the relationship between corporate governance and earnings opacity in China.
Design/methodology/approach
Two corporate governance mechanisms form the basis of the analysis: 1) the board of directors and 2) the external audit function. OLS regression analysis is employed on a large sample from 2000 to 2014 with 20,235 firm-year observations.
Findings
Corporate governance is found to be associated with reduced levels of earnings opacity for Chinese listed companies. Furthermore, the association between corporate governance and reduced levels of earnings opacity strengthened after the implementation of various key reforms.
Practical implications
Chinese regulators are advised to proceed with caution as not all Western approaches to corporate governance are transferrable to the Chinese setting.
Originality/value
This study contributes to the literature by analyzing broad latent constructs of corporate governance in addition to individual observable dimensions in order to reveal that various key reforms have been successful in strengthening the link between governance and reporting quality for Chinese listed companies.
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