Wet steam condensing flow in low-pressure steam turbine leads to efficiencylosses and blade erosions. In order to investigate this problem by numerical approach, anEulerian/Eulerian model has been developed, in which ...Wet steam condensing flow in low-pressure steam turbine leads to efficiencylosses and blade erosions. In order to investigate this problem by numerical approach, anEulerian/Eulerian model has been developed, in which the wet steam is regarded as mixture comprisingtwo coupled systems: the vapor phase and the liquid phase. These two systems are both described byconservation equations. High resolution TVD scheme is employed to capture condensing phenomena inwet steam flow. This model has been validated by numerical simulations of condensing flows in 1D and2D nozzles. Compared with experimental data, a good agreement is observed. This Eulerian/Eulerianmodel can be extended to 3D calculation of condensing flow.展开更多
Removal of condensates from wet steam flow in the last stages of steam turbines significantly promotes stage efficiency and prevents erosion of rotors. In this paper, homogeneous spontaneous condensation in transonic ...Removal of condensates from wet steam flow in the last stages of steam turbines significantly promotes stage efficiency and prevents erosion of rotors. In this paper, homogeneous spontaneous condensation in transonic steam flow in the 2-D rotor-tip section of a stage turbine is investigated. Calculated results agree with experimental data reasonably well. On the basis of the above work, a 2-D numerical simulation of wet steam flow in adjacent root sections of a complex steam turbine stage was carded out. Computational results were analyzed and provide insights into effective removal of humidity.展开更多
In this paper, an improvement of heating method for measuring wetness of the flowing wet steam is developed, the basic principle of the heating method is presented and the mathematical model has been built for analyzi...In this paper, an improvement of heating method for measuring wetness of the flowing wet steam is developed, the basic principle of the heating method is presented and the mathematical model has been built for analyzing the thermodynamics problezns during the process of heating. Moreover, an instru-ment for measuring wetness of wet steam flow was designed and made out. This instrument has been used for measuring wetness of the wet steam flow at the outlet of the nozzle rig in Thermal TUrbine Laboratory Xi’an Jiaotong University. By analyzing the relative error of the result, it was found that this instrument has fairly high accuracy it can be used as the prototype of practical instrument and has an important applicable value in engineering.展开更多
A new dual-fluid model considering phase ansition and velocity slip was proposed in this paper and the Cunningham correction was used in the droplet resistance calculation. This dual-fluid model was applied to the num...A new dual-fluid model considering phase ansition and velocity slip was proposed in this paper and the Cunningham correction was used in the droplet resistance calculation. This dual-fluid model was applied to the numerical simulations of wet steam flow in a 2D LAVAL nozzle and in the White cascade respectively. The results of two simulations demonstrate that the model is reliable. Meanwhile, the spontaneous condensing flow in White cascade was analyzed and it infers that the irreversible loss caused by condensation accounts for the largest share （about 8.78% of inlet total pressure） in total pressure loss while the loss caused by velocity slip takes the smallest share （nearly 0.42%）, and another part of total pressure loss caused by pneumatic factors contributes a less share than condensation, i.e. almost 3.95% of inlet total pressure.展开更多
Experimental investigations of non-equilibrium spontaneous condensation in transonic steam flow were carded out in linear blade cascade. The linear cascade consists of the stator blades of the last stage of low pressu...Experimental investigations of non-equilibrium spontaneous condensation in transonic steam flow were carded out in linear blade cascade. The linear cascade consists of the stator blades of the last stage of low pressure steam turbine. The applied experimental test section is a part of a small scale steam power plant located at Silesian Uni- versity of Technology in Gliwice. The steam parameters at the test section inlet correspond to the real conditions in low pressure part of 200MWe steam turbine. The losses in the cascade were estimated using measured static pressure and temperature behind the cascade and the total parameters at inlet. The static pressure measurements on the blade surface as well as the Schlieren pictures were used to assess the flow field in linear cascade of steam turbine stator blades.展开更多
Based on the two-phase wet steam flow with spontaneous condensation, experimental verification and flow analysis on nozzle and 2D cascade are carried out. The 3D Reynolds-Averaged gas-liquid two-phase flow control equ...Based on the two-phase wet steam flow with spontaneous condensation, experimental verification and flow analysis on nozzle and 2D cascade are carried out. The 3D Reynolds-Averaged gas-liquid two-phase flow control equation solver is explored with k-e-kp turbulence model. Furthermore, 3D flow numerical simulation on the last stage stator of the steam turbine is carried out. The results show that a sudden pressure rise on blade suction surface is mainly caused by the droplet growth in condensation flow. The more backward the condensation position is in cascade passage, the less the sudden pressure rise from condensation is, and the larger the nucleation rate is, the maximum under-cooling and the number of droplets per unit volume are. Interaction of condensation wave and shock wave has imposed greater influence on the parameters of the blade cascade outlet.展开更多
A mathematical model for predicting the behavior of wet steam flow in the vicinity of the intake head of the sampling probe is presented. The vapor flow field and droplet trajectory in the calculated region have been ...A mathematical model for predicting the behavior of wet steam flow in the vicinity of the intake head of the sampling probe is presented. The vapor flow field and droplet trajectory in the calculated region have been obtained. The errors caused by non-isokinetic sampling for different conditions have been analyzed and the analytical results would provide useful data for the design and application of a heating method-based wetness measurement probe in practice.展开更多
The effects of Reactive Black 5 utilized to cotton fabrics by short wet-steam process on the dyeing properties were investigated. This study will provide a theoretical reference for short wet-steam process of cotton f...The effects of Reactive Black 5 utilized to cotton fabrics by short wet-steam process on the dyeing properties were investigated. This study will provide a theoretical reference for short wet-steam process of cotton fabrics with bifunctional reactive dyes. The optimal amount of Selilao agent was 20 g/L, while the soaping and rubbing fastness of the dyed cotton fabrics were both reached to 4-5 rating.展开更多
Introduction： There are several components in motion before steam reaches its destination. Each element plays a significant role in generating adequate steam for terminal sterilization of critical devices. The knowl...Introduction： There are several components in motion before steam reaches its destination. Each element plays a significant role in generating adequate steam for terminal sterilization of critical devices. The knowledge and awareness of factors that contribute to wet packs will assist in maximizing steam quality. Steam sterilization of critical devices such as surgical instruments in the acute care setting is fundamentally necessary to prevent infection. Sterile packaging that is wet after removal from the autoclave is considered contaminated. This wet pack presents a significant infection risk and indicates a defect in the sterilization process. The identification of wet packs prompted the exploration of the sterilization process. In reviewing the evolution of steam production, our investigation began in the boiler room. The assessments of the boiler operations, steam quality, and loading technique of the autoclaves were examined as possible contributing factors in the propagation of wet packs. Methods： The investigation was performed in a 592-bed non-teaching acute care facility in New Jersey. Methods to ensure the integrity of steam included; a cut point of 〈 3,500 ppm TDSs （total dissolved solids）, （daily） calibration of the TDS analyzer to ensure accurate TDS measurement, increase in autoclave drying times, reduction of the weight density of surgical trays from 25 lbs. to 20 lbs., and revision of sterilization loading practices. Modifications were implemented from June 2015 to December 2015. Results： No wet packs were identified from January through May 2016. In June 2016, 2 wet packs were detected, and upon further analysis there was an increase in the water level of the boiler drum. After this special cause variation, no wet packs have been identified. Conclusion： The monitoring and documentation of boiler room parameters and CSP （central sterile processing） practice modifications may have impacted the reduction of wet pack.展开更多
基金This project is supported by National Natural Science Foundation of China (No.50176035)Doctorate Foundation of Xi'an Jiaotong University,China (No.DFXJU2000-18)
文摘Wet steam condensing flow in low-pressure steam turbine leads to efficiencylosses and blade erosions. In order to investigate this problem by numerical approach, anEulerian/Eulerian model has been developed, in which the wet steam is regarded as mixture comprisingtwo coupled systems: the vapor phase and the liquid phase. These two systems are both described byconservation equations. High resolution TVD scheme is employed to capture condensing phenomena inwet steam flow. This model has been validated by numerical simulations of condensing flows in 1D and2D nozzles. Compared with experimental data, a good agreement is observed. This Eulerian/Eulerianmodel can be extended to 3D calculation of condensing flow.
文摘Removal of condensates from wet steam flow in the last stages of steam turbines significantly promotes stage efficiency and prevents erosion of rotors. In this paper, homogeneous spontaneous condensation in transonic steam flow in the 2-D rotor-tip section of a stage turbine is investigated. Calculated results agree with experimental data reasonably well. On the basis of the above work, a 2-D numerical simulation of wet steam flow in adjacent root sections of a complex steam turbine stage was carded out. Computational results were analyzed and provide insights into effective removal of humidity.
文摘In this paper, an improvement of heating method for measuring wetness of the flowing wet steam is developed, the basic principle of the heating method is presented and the mathematical model has been built for analyzing the thermodynamics problezns during the process of heating. Moreover, an instru-ment for measuring wetness of wet steam flow was designed and made out. This instrument has been used for measuring wetness of the wet steam flow at the outlet of the nozzle rig in Thermal TUrbine Laboratory Xi’an Jiaotong University. By analyzing the relative error of the result, it was found that this instrument has fairly high accuracy it can be used as the prototype of practical instrument and has an important applicable value in engineering.
基金support for this work by the fundamental research funds for the Cen-tral Universities (Grant No. HIT. NSRIF. 201173)
文摘A new dual-fluid model considering phase ansition and velocity slip was proposed in this paper and the Cunningham correction was used in the droplet resistance calculation. This dual-fluid model was applied to the numerical simulations of wet steam flow in a 2D LAVAL nozzle and in the White cascade respectively. The results of two simulations demonstrate that the model is reliable. Meanwhile, the spontaneous condensing flow in White cascade was analyzed and it infers that the irreversible loss caused by condensation accounts for the largest share （about 8.78% of inlet total pressure） in total pressure loss while the loss caused by velocity slip takes the smallest share （nearly 0.42%）, and another part of total pressure loss caused by pneumatic factors contributes a less share than condensation, i.e. almost 3.95% of inlet total pressure.
基金supported by the National Science Centre funds within the project with nr.2011/03/B/ST8/06425
文摘Experimental investigations of non-equilibrium spontaneous condensation in transonic steam flow were carded out in linear blade cascade. The linear cascade consists of the stator blades of the last stage of low pressure steam turbine. The applied experimental test section is a part of a small scale steam power plant located at Silesian Uni- versity of Technology in Gliwice. The steam parameters at the test section inlet correspond to the real conditions in low pressure part of 200MWe steam turbine. The losses in the cascade were estimated using measured static pressure and temperature behind the cascade and the total parameters at inlet. The static pressure measurements on the blade surface as well as the Schlieren pictures were used to assess the flow field in linear cascade of steam turbine stator blades.
文摘Based on the two-phase wet steam flow with spontaneous condensation, experimental verification and flow analysis on nozzle and 2D cascade are carried out. The 3D Reynolds-Averaged gas-liquid two-phase flow control equation solver is explored with k-e-kp turbulence model. Furthermore, 3D flow numerical simulation on the last stage stator of the steam turbine is carried out. The results show that a sudden pressure rise on blade suction surface is mainly caused by the droplet growth in condensation flow. The more backward the condensation position is in cascade passage, the less the sudden pressure rise from condensation is, and the larger the nucleation rate is, the maximum under-cooling and the number of droplets per unit volume are. Interaction of condensation wave and shock wave has imposed greater influence on the parameters of the blade cascade outlet.
文摘A mathematical model for predicting the behavior of wet steam flow in the vicinity of the intake head of the sampling probe is presented. The vapor flow field and droplet trajectory in the calculated region have been obtained. The errors caused by non-isokinetic sampling for different conditions have been analyzed and the analytical results would provide useful data for the design and application of a heating method-based wetness measurement probe in practice.
文摘The effects of Reactive Black 5 utilized to cotton fabrics by short wet-steam process on the dyeing properties were investigated. This study will provide a theoretical reference for short wet-steam process of cotton fabrics with bifunctional reactive dyes. The optimal amount of Selilao agent was 20 g/L, while the soaping and rubbing fastness of the dyed cotton fabrics were both reached to 4-5 rating.
文摘Introduction： There are several components in motion before steam reaches its destination. Each element plays a significant role in generating adequate steam for terminal sterilization of critical devices. The knowledge and awareness of factors that contribute to wet packs will assist in maximizing steam quality. Steam sterilization of critical devices such as surgical instruments in the acute care setting is fundamentally necessary to prevent infection. Sterile packaging that is wet after removal from the autoclave is considered contaminated. This wet pack presents a significant infection risk and indicates a defect in the sterilization process. The identification of wet packs prompted the exploration of the sterilization process. In reviewing the evolution of steam production, our investigation began in the boiler room. The assessments of the boiler operations, steam quality, and loading technique of the autoclaves were examined as possible contributing factors in the propagation of wet packs. Methods： The investigation was performed in a 592-bed non-teaching acute care facility in New Jersey. Methods to ensure the integrity of steam included; a cut point of 〈 3,500 ppm TDSs （total dissolved solids）, （daily） calibration of the TDS analyzer to ensure accurate TDS measurement, increase in autoclave drying times, reduction of the weight density of surgical trays from 25 lbs. to 20 lbs., and revision of sterilization loading practices. Modifications were implemented from June 2015 to December 2015. Results： No wet packs were identified from January through May 2016. In June 2016, 2 wet packs were detected, and upon further analysis there was an increase in the water level of the boiler drum. After this special cause variation, no wet packs have been identified. Conclusion： The monitoring and documentation of boiler room parameters and CSP （central sterile processing） practice modifications may have impacted the reduction of wet pack.
