Utilization of wind energy is a promising way to generate power,and wind turbine blades play a key role in collecting the wind energy effectively.This paper attempts to measure the deformation parameter of wind turbin...Utilization of wind energy is a promising way to generate power,and wind turbine blades play a key role in collecting the wind energy effectively.This paper attempts to measure the deformation parameter of wind turbine blades in mechanics experiments using a videometric method. In view that the blades experience small buckling deformation and large integral deformation simultaneously, we proposed a parallel network measurement(PNM) method including the key techniques such as camera network construction,camera calibration,distortion correction,the semi-automatic high-precision extraction of targets,coordinate systems unification,and bundle adjustment,etc. The relatively convenient construction method of the measuring system can provide an abundant measuring content,a wide measuring range and post processing.The experimental results show that the accuracy of the integral deformation measurement is higher than 0.5 mm and that of the buckling deformation measurement higher than 0.1mm.展开更多
This paper aims to investigate the measurement uncertainty of blade surface by coordinates measuring machines (CMMs) in different sampling modes.Two different sampling methods for the blade surface, which are the para...This paper aims to investigate the measurement uncertainty of blade surface by coordinates measuring machines (CMMs) in different sampling modes.Two different sampling methods for the blade surface, which are the parallel mode and the rotation mode, are studied to examine their measurement uncertainty.The fundamental principles and operational processes of the two modes are presented and discussed.The measurements were performed on a twisted-face blade, and data processing was also conducted to fit the cross-section profile both of the base surface and back surface separately.Then the measurement uncertainties of two sampling methods were evaluated on different parts of the blade surface in terms of the surface profile’s curvature and twist rate.It is found that the measurement of blade surface by CMMs shows much uncertainty for both of the sampling modes because of the complexity of the blade surface.The back surface’s measurement uncertainty is larger than that of the base surface.The measurement uncertainty of cross-section profiles on the top blade surface is larger than that of the bottom blade surface.In addition, the difference between the measurement uncertainties of two sampling methods is small, especially for the base blade surface.The research means that both sampling methods can be a practical application choice for the measurement of blade surface by CMMs.展开更多
Helicopter blade running elevation measurement is an important measure target in helicopter blade dynamic balance experimentation. The elevation influences the helicopter's security and other performance capabilit...Helicopter blade running elevation measurement is an important measure target in helicopter blade dynamic balance experimentation. The elevation influences the helicopter's security and other performance capabilities. In testing, however, it has been difficult to measure the elevation when the rotor reaches high speeds. To get a simple, fast and highly accurate measurement system, photo electricity technology was applied to measuring the blade running elevation. Discussed is the measurement principle of blade running elevation, the design of the measurement system and analysis of the measurement precision.展开更多
During heat treatment process, the distortion behavior inevitably appears in hydraulic turbine blade castings. In this research, a technology was developed for real-time measurement of the distortion in hydraulic turb...During heat treatment process, the distortion behavior inevitably appears in hydraulic turbine blade castings. In this research, a technology was developed for real-time measurement of the distortion in hydraulic turbine blade castings at the still air cooling and forced air cooling stages during heat treatment process. The method was used to measure the distortion behavior at the cooling stages in both normalizing and tempering processes. At the normalization, the distortion at the blade corner near outlet side undergoes four stages with alternating bending along positive and negative directions. At the tempering stage, the distortion could be divided into two steps. The temperature difference between the two surfaces of blade casting was employed to analyze the distortion mechanism. The measured results could be applied to guide the production, and the machining allowance could be reduced by controlling the distortion behavior.展开更多
Quantitative measurement of the cutter blade sharpness is yet a difficult problem, since so far there has been no appropriate testing method. In this paper, a technique is introduced for measuring the cutter blade sha...Quantitative measurement of the cutter blade sharpness is yet a difficult problem, since so far there has been no appropriate testing method. In this paper, a technique is introduced for measuring the cutter blade sharpness at different testing conditions. The sharpness of cutter blades are measured by detecting the force to cut off the fiber with a material strength testing machine, and the results indicated that the technique could be used to measure the cutter blade sharpness satisfactorily. The fiber tension and downward speed of cutter blades are recommended to be 4.9 cN and 50 mm/min respectively for cutting 0.22 mm PET fiber.展开更多
Distortion during the forging or machining processes of a blade causes problems in subsequent manufacturing. This paper proposes an alternative multipoint correction method integrated with blade measurement, determina...Distortion during the forging or machining processes of a blade causes problems in subsequent manufacturing. This paper proposes an alternative multipoint correction method integrated with blade measurement, determination of correcting parameters, and adjustment of the correcting die. An iterative algorithm for determining the correcting parameters is proposed. Measuring equipment combining a laser displacement sensor with multipoint flexible support is manufactured to measure the blade shape. Multipoint correcting equipment with an adaptive lower die and rapid adjustment is manufactured, and software is developed for data analysis and equipment control. The correction experiment for a rough-machined steam-turbine blade indicates that the correcting parameters can be determined after one modification based on numerical simulation, and that a rough blade that meets the allowance for finish machining can be obtained using the determined correction parameters.展开更多
The inherent unsteady pressure fluctuations on the rotating blade suction surface of an axial compressor were experimentally measured by directly mounting five high response miniature pressure transducers into the rot...The inherent unsteady pressure fluctuations on the rotating blade suction surface of an axial compressor were experimentally measured by directly mounting five high response miniature pressure transducers into the rotor blade along a streamline at 50% span respectively. The results show that the unsteady pressure fluctuations of rotor blade surface could be measured successfully by this means. The relations about the period, altitude of unsteady pressure with rotating speed, the discipline of pressure fluctuation along the streamwise direction were obtained.展开更多
文摘Utilization of wind energy is a promising way to generate power,and wind turbine blades play a key role in collecting the wind energy effectively.This paper attempts to measure the deformation parameter of wind turbine blades in mechanics experiments using a videometric method. In view that the blades experience small buckling deformation and large integral deformation simultaneously, we proposed a parallel network measurement(PNM) method including the key techniques such as camera network construction,camera calibration,distortion correction,the semi-automatic high-precision extraction of targets,coordinate systems unification,and bundle adjustment,etc. The relatively convenient construction method of the measuring system can provide an abundant measuring content,a wide measuring range and post processing.The experimental results show that the accuracy of the integral deformation measurement is higher than 0.5 mm and that of the buckling deformation measurement higher than 0.1mm.
基金Sponsored by the National Natural Science Foundation of China(Grant No.11572098)
文摘This paper aims to investigate the measurement uncertainty of blade surface by coordinates measuring machines (CMMs) in different sampling modes.Two different sampling methods for the blade surface, which are the parallel mode and the rotation mode, are studied to examine their measurement uncertainty.The fundamental principles and operational processes of the two modes are presented and discussed.The measurements were performed on a twisted-face blade, and data processing was also conducted to fit the cross-section profile both of the base surface and back surface separately.Then the measurement uncertainties of two sampling methods were evaluated on different parts of the blade surface in terms of the surface profile’s curvature and twist rate.It is found that the measurement of blade surface by CMMs shows much uncertainty for both of the sampling modes because of the complexity of the blade surface.The back surface’s measurement uncertainty is larger than that of the base surface.The measurement uncertainty of cross-section profiles on the top blade surface is larger than that of the bottom blade surface.In addition, the difference between the measurement uncertainties of two sampling methods is small, especially for the base blade surface.The research means that both sampling methods can be a practical application choice for the measurement of blade surface by CMMs.
文摘Helicopter blade running elevation measurement is an important measure target in helicopter blade dynamic balance experimentation. The elevation influences the helicopter's security and other performance capabilities. In testing, however, it has been difficult to measure the elevation when the rotor reaches high speeds. To get a simple, fast and highly accurate measurement system, photo electricity technology was applied to measuring the blade running elevation. Discussed is the measurement principle of blade running elevation, the design of the measurement system and analysis of the measurement precision.
基金supported financially by the National Eleventh Five-Year Science and Technology Support Program of China through Grant No.2007BAF02B02Major National Sci-Tech Project of China No 2011ZX04014-052
文摘During heat treatment process, the distortion behavior inevitably appears in hydraulic turbine blade castings. In this research, a technology was developed for real-time measurement of the distortion in hydraulic turbine blade castings at the still air cooling and forced air cooling stages during heat treatment process. The method was used to measure the distortion behavior at the cooling stages in both normalizing and tempering processes. At the normalization, the distortion at the blade corner near outlet side undergoes four stages with alternating bending along positive and negative directions. At the tempering stage, the distortion could be divided into two steps. The temperature difference between the two surfaces of blade casting was employed to analyze the distortion mechanism. The measured results could be applied to guide the production, and the machining allowance could be reduced by controlling the distortion behavior.
文摘Quantitative measurement of the cutter blade sharpness is yet a difficult problem, since so far there has been no appropriate testing method. In this paper, a technique is introduced for measuring the cutter blade sharpness at different testing conditions. The sharpness of cutter blades are measured by detecting the force to cut off the fiber with a material strength testing machine, and the results indicated that the technique could be used to measure the cutter blade sharpness satisfactorily. The fiber tension and downward speed of cutter blades are recommended to be 4.9 cN and 50 mm/min respectively for cutting 0.22 mm PET fiber.
基金supported in part by the Fundamental Research Funds for the Central Universities(Grant Nos.xtr012019004 and zrzd2017027)the Shaanxi Province Key Research and Development Projects(Grant No.2021GXLH-Z-049).
文摘Distortion during the forging or machining processes of a blade causes problems in subsequent manufacturing. This paper proposes an alternative multipoint correction method integrated with blade measurement, determination of correcting parameters, and adjustment of the correcting die. An iterative algorithm for determining the correcting parameters is proposed. Measuring equipment combining a laser displacement sensor with multipoint flexible support is manufactured to measure the blade shape. Multipoint correcting equipment with an adaptive lower die and rapid adjustment is manufactured, and software is developed for data analysis and equipment control. The correction experiment for a rough-machined steam-turbine blade indicates that the correcting parameters can be determined after one modification based on numerical simulation, and that a rough blade that meets the allowance for finish machining can be obtained using the determined correction parameters.
文摘The inherent unsteady pressure fluctuations on the rotating blade suction surface of an axial compressor were experimentally measured by directly mounting five high response miniature pressure transducers into the rotor blade along a streamline at 50% span respectively. The results show that the unsteady pressure fluctuations of rotor blade surface could be measured successfully by this means. The relations about the period, altitude of unsteady pressure with rotating speed, the discipline of pressure fluctuation along the streamwise direction were obtained.