scholarly journals Variable-Diameter Drum with Concentric Threshing Gap and Performance Comparison Experiment

2020 ◽  
Vol 10 (15) ◽  
pp. 5386
Author(s):  
Yaoming Li ◽  
Zhan Su ◽  
Zhenwei Liang ◽  
Yu Li
Keyword(s):  
Power Consumption ◽  
Loss Rate ◽  
Axial Flow ◽  
Performance Comparison ◽  
Adjustment Method ◽  
Damage Rate ◽  
Variable Diameter ◽  
Combine Harvester ◽  
The Difference ◽  
And Performance

The threshing gap of the thresher device for rice combine harvester has to be adjusted in real time based on different feed rates to ensure the operation efficiency in the harvesting process. However, adjusting the threshing gap by changing the position of concave grid may result in unevenness of threshing gap of the thresher device and further impact on the fluidity of material in the thresher device; in addition, it is also unavailable to adjust the threshing gap by changing the drum diameter when the rice combine harvester is in operation. In view of the above and based on axial flow threshing drum, the design of a variable-diameter threshing drum available for overall and rapid drum diameter adjustment and the research on diameter adjustment device as well as electronic control self-locking device were introduced in this study. Besides, stress analysis was implemented to the diameter adjustment device to ensure the stability of the variable-diameter threshing drum. Field experiment was implemented to identify the difference between the impacts brought to the threshing performance (grain-entrainment loss rate, damage rate, threshing efficiency, and threshing power consumption) by both methods for threshing gap adjustment. The experiment result shows that the drum adjustment method with variable-diameter drum features higher grain-entrainment loss rate, threshing efficiency, and threshing power consumption, yet stable in terms of consumption fluctuation, but a lower damage rate than their counterparts with concave adjustment method.

scholarly journals Design and performance test of variable diameter threshing drum of combine harvester

2021 ◽  
Author(s):  
Zhan Su ◽  
Zhao Ding ◽  
Liquan Tian ◽  
Xue Lin ◽  
Zhiming Wang
Keyword(s):  
Performance Test ◽  
Variable Diameter ◽  
Combine Harvester ◽  
And Performance

Compressor Erosion and Performance Deterioration

1987 ◽  
Vol 109 (3) ◽  
pp. 297-306 ◽  
Author(s):  
W. Tabakoff
Keyword(s):  
Axial Flow ◽  
Solid Particles ◽  
Atmospheric Environment ◽  
Jet Engines ◽  
Particle Trajectories ◽  
Performance Deterioration ◽  
The Difference ◽  
And Performance ◽  
Flow Compressor ◽  
Particle Separator

Aircraft engines operating in areas where the atmosphere is polluted by small solid particles are typical examples of jet engines operating under hostile atmospheric environment. The particles may be different kinds of sand, volcanic ashes or others. Under these conditions, the gas and particles experience different degrees of turning as they flow through the engine. This is mainly due to the difference in their inertia. This paper presents the results of an investigation of the solid particle dynamics through a helicopter engine with inlet particle separator. The particle trajectories are computed in the inlet separator which is characterized by considerable hub and tip contouring and radial variation in the swirling vane shape. The nonseparated particle trajectories are determined through the deswirling vanes and the five stage axial flow compressor. The results from this study include the frequency of particle impacts and the erosion distribution on the blade surfaces.

Flow Analysis of Axial Compressor AV63-15 Variable Stator Simulation

2012 ◽  
Vol 532-533 ◽  
pp. 474-478
Author(s):  
Wei Hua Cheng ◽  
Mian Chang Li ◽  
Chuan Peng Li
Keyword(s):  
Flow Analysis ◽  
Three Dimensional ◽  
Axial Compressor ◽  
Axial Flow ◽  
Operating Conditions ◽  
Axial Flow Compressor ◽  
Air Supply ◽  
The Difference ◽  
And Performance ◽  
Flow Compressor

This paper conducts numerical simulation to a 15-stage civil axial flow compressor and obtains its main parameters distribution and performance curve by a full three-dimensional viscid flow computation software. The computation result indicates that, the developed axial flow compressor meets the anticipated design requirements, and satisfies the customers’ indicators. Under the designed compression ratio, the difference between the maximum air supply quantity in summer and the minimum air supply quantity in winter is 22%. By comparing the operating conditions and data analysis, obtained the change trend of axial velocity, static pressure and temperature, and Ma, and discovered that, under opening of 48° and outlet back pressure of 550KPa, flow separation occurred on the section of machine set close to hud, which indicated that operating condition was close to surging condition.

scholarly journals Performance Comparison and Evaluation of Two Small Chili Pepper Harvester Prototypes That Attach to Walking Cultivators

2020 ◽  
Vol 10 (7) ◽  
pp. 2570
Author(s):  
Tae-Hyeong Kim ◽  
Dae-Cheol Kim ◽  
Yongjin Cho
Keyword(s):  
Loss Rate ◽  
Field Performance ◽  
Performance Comparison ◽  
Chili Pepper ◽  
Performance Tests ◽  
Harvest Efficiency ◽  
The Difference ◽  
Main Frame

Two prototypes of small chili pepper harvesters that attach to walking cultivators were designed and manufactured before field performance tests were conducted. The two prototypes were designed and manufactured with different main frame materials, forms of divider, picking guides, and helix rotation speeds. The maximum helix speed of the first prototype was 500 rpm, and the helix rotation speeds of the second prototype were a minimum of 510 rpm and a maximum of 730 rpm. Field performance tests were conducted on two species of chili, the AR Legend and the Jeokyoung, to determine which was suitable for mechanization. The Jeokyoung species was found to be most suitable for mechanization as its harvest efficiency was higher and its pepper left on plant rate and ground fall loss rate were lower than AR Legend’s. When the first and second prototypes were compared at helix rotation speeds of 500 to 510 rpm, in the case of the AR Legend, the average harvest efficiency of the second prototype was higher than the first prototype by 2.2%, the average pepper left on plant rate was lower by 2.1%, and the average ground fall loss rate was lower by 3.9%. In the case of the Jeokyoung, the performance of the second prototype was further improved over the first prototype as the average harvest efficiency increased to 5.2%, and the difference in average ground fall loss rate increased to 8.8%.

scholarly journals Study on Performance of Concentric Threshing Device with Multi-Threshing Gaps for Rice Combines

Agriculture ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 1000
Author(s):  
Yanbin Liu ◽  
Yaoming Li ◽  
Lipeng Chen ◽  
Tao Zhang ◽  
Zhenwei Liang ◽  
...  
Keyword(s):  
Discrete Element Method ◽  
Loss Rate ◽  
Total Loss ◽  
Factors Affecting ◽  
Damage Rate ◽  
Grain Damage ◽  
Combine Harvester ◽  
Main Factors ◽  
Simulation Results ◽  
Combine Harvesters

S concentric threshing device can improve rice crop separation and transportation capabilities. As one of the main factors affecting the threshing performance of rice combine harvesters, the threshing gap can influence the grain unthreshed rate and the grain damage rate directly. However, the clearance between any threshing cylinder tooth and the concave grid is constant for the traditional threshing device, named the single threshing gap in this paper, resulting in a consistently high total loss rate (the sum of unthreshed and damaged grains). Therefore, multi-threshing gaps are proposed in this paper for the concentric threshing device to solve the above problem. To compare the threshing performance between the single threshing gap and the multi-threshing gaps, the movement process of rice mixture (grain, short straw, and long straw) was simulated using the discrete element method (DEM). The simulation results showed that the separation and transportation abilities of the multi-threshing gaps were not decreased, but the distribution of threshed output mixture was more even for the multi-threshing gaps. Furthermore, a field experiment was also carried out on a combine harvester to compare the total loss rate. The experiment results showed that the total loss rate of the concentric threshing device with multi-threshing gaps was reduced by 0.0593%, which was 5.77% less than the total loss rate of the concentric threshing device with a single threshing gap.

Design of Longitudinal Axial Flow Threshing and Separating Device of Maize Grain Combine Harvester

2017 ◽  
Vol 863 ◽  
pp. 251-254
Author(s):  
Kun Zhang ◽  
Shu Kun Cao ◽  
Xiu Sheng Chen ◽  
Chong Cao ◽  
Chang Zhong Wu
Keyword(s):  
Feeding Rate ◽  
Axial Flow ◽  
Development Trend ◽  
Damage Rate ◽  
Modern Maize ◽  
Cleaning Device ◽  
Spiral Blade ◽  
Combine Harvester ◽  
Maize Grain ◽  
The Development Trend

Harvesting grain directly has been the development trend of modern maize combine harvester. To satisfy the demand of harvesting grain straightly type maize combine harvester for large feeding rate, low damage rate, high threshing rate, the longitudinal axial flow threshing and separating device was designed. It could also increase the separating rate of grain and miscellaneous, and reduce the burden of cleaning device. Threshing gap was adjustable in the range of 30 to 60mm, which reduced the incidence of jam faults effectively in the threshing process. Spiral blade on feeder, threshing rasp-bar and separating nail were replaceable, which improved the efficiency for threshing and separating.

A Modification of the Payne-Jones Method of Identifying Abnormal Differences in WISC-R Performance and Verbal IQ's

1996 ◽  
Vol 12 (1) ◽  
pp. 27-32 ◽  
Author(s):  
Louis M. Hsu
Keyword(s):  
Full Scale ◽  
True Score ◽  
Verbal Iq ◽  
Score Difference ◽  
The Difference ◽  
And Performance

The difference (D) between a person's Verbal IQ (VIQ) and Performance IQ (PIQ) has for some time been considered clinically meaningful ( Kaufman, 1976 , 1979 ; Matarazzo, 1990 , 1991 ; Matarazzo & Herman, 1985 ; Sattler, 1982 ; Wechsler, 1984 ). Particularly useful is information about the degree to which a difference (D) between scores is “abnormal” (i.e., deviant in a standardization group) as opposed to simply “reliable” (i.e., indicative of a true score difference) ( Mittenberg, Thompson, & Schwartz, 1991 ; Silverstein, 1981 ; Payne & Jones, 1957 ). Payne and Jones (1957) proposed a formula to identify “abnormal” differences, which has been used extensively in the literature, and which has generally yielded good approximations to empirically determined “abnormal” differences ( Silverstein, 1985 ; Matarazzo & Herman, 1985 ). However applications of this formula have not taken into account the dependence (demonstrated by Kaufman, 1976 , 1979 , and Matarazzo & Herman, 1985 ) of Ds on Full Scale IQs (FSIQs). This has led to overestimation of “abnormality” of Ds of high FSIQ children, and underestimation of “abnormality” of Ds of low FSIQ children. This article presents a formula for identification of abnormal WISC-R Ds, which overcomes these problems, by explicitly taking into account the dependence of Ds on FSIQs.

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