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Zhou L.,Nanjing Research Institute of Agricultural Mechanization | Zhang X.,Nanjing Forestry University | Lu X.,Nanjing Research Institute of Agricultural Mechanization | Ding S.,Nanjing Research Institute of Agricultural Mechanization
Nongye Jixie Xuebao/Transactions of the Chinese Society of Agricultural Machinery | Year: 2012

In order to investigate the characteristic of properties of the disc atomizer, the experimental and computational simulation methods were adopted. The optimum working rotational speed and the air velocity field at different rotational speeds of the disc atomizer were studied and validated by the experiment data. The results showed that the optimum rotational speed was 1400 r/min at the selected impeller. The velocity field of the disc atomizer was axial symmetry. The velocity of central plane diffused at a fixed angle and decayed along the centre line. The simulation data was closely related to the experiment data.


Wang S.,Nanjing Agricultural University | Wang S.,Anhui Polytechnic University | Hu Z.,Nanjing Research Institute of Agricultural Mechanization | Han Y.,Nanjing Agricultural University | Gu Z.,Nanjing Agricultural University
Drying Technology | Year: 2013

The effects of magnetron arrangement and microwave power combination on the drying uniformity of carrot were investigated in this study. The drying uniformity was influenced by magnetron location and quantity. Using one magnetron resuted in poor drying uniformity. However, when two magnetrons were applied, the drying uniformity was 80% after drying for 16 min, which was 93.49% when power combination of three magnetrons at powers of 400, 500, and 600 W were used. The optimal magnetron locations and a suitable microwave power combinations were determined to improve the drying uniformity of carrot. © 2013 Copyright Taylor and Francis Group, LLC.


Zhou L.,Nanjing Research Institute of Agricultural Mechanization | Fu X.,Nanjing Research Institute of Agricultural Mechanization | Xue X.,Nanjing Research Institute of Agricultural Mechanization | Kong W.,Nanjing Research Institute of Agricultural Mechanization | Qiu W.,Nanjing Agricultural University
Nongye Jixie Xuebao/Transactions of the Chinese Society for Agricultural Machinery | Year: 2013

The jet mixing apparatus (JMA) is an important part for mixing the water with the pesticide, which has good prospect in large plant protection machinery. The parameter of area ratio, area of nozzle and distance between nozzle and mixing chamber were discussed by theoretical analysis. The standard k-ε two-equation model was adopted to simulate the interior flow field. Combined with experiment data, the performance characteristics, the effects of structural parameters on the JMA property were discussed. Results showed that the optimum area ratio was related to working pressure, outlet pressure and jet pressure. The distance between nozzle and mixing chamber should be equal to optimum extent of free stream. The maximum relative error and average error of relative pressure at different area ratio were 0.125 and 0.051, respectively. The numerical model and simulation method were validated validate to meet the requirements of engineering. The jet flow decreased when the relative pressure greater than 0.3. The maximum relative pressure was between 0.5 and 0.6 under different available pressures. The optimum area ratio of JMA was between 1.6 and 2.0. The optimum distance between nozzle and mixing chamber was between 2.6 mm and 4.6 mm.


Yan J.,Nanjing Research Institute of Agricultural Mechanization | Xie H.,Nanjing Research Institute of Agricultural Mechanization | Hu Z.,Nanjing Research Institute of Agricultural Mechanization | Wei H.,Nanjing Research Institute of Agricultural Mechanization | And 2 more authors.
Nongye Gongcheng Xuebao/Transactions of the Chinese Society of Agricultural Engineering | Year: 2015

In recent years, with the rapid development of harvest mechanization in China, the whole level of wheat harvest mechanization has been more than 90%. The current sun-drying facilities in Chinese rural areas are far from being able to meet the requirements of post-harvest drying of wet wheat. Mechanical drying is gradually considered to reduce post-harvest losses of crops in Chinese rural areas. As an economical and practical grain dryer, bin-ventilation dryer is considerably fitting for Chinese rural production practice. However, such devices are always without recommended work parameters for different crops under different ambient conditions and different initial moisture contents of material, so a large sum of energy is wasted in drying process. In order to obtain the best work parameters for a self-developed bin-ventilation dryer whose ventilation direction could be changed by manual operation, a set of partial differential equation models for wheat drying of fixed bed were developed, which reflected the relationships of heat and mass transfer between material and air during the drying process. On this basis, for the unique characteristics of upward and downward reversing ventilating, the partial differential equation models were discretized by forward finite difference method. Besides, the simulation program of upward and downward reversing ventilating drying of fixed-bed wheat was written by software. Through the simulation program, real-time drying status of wheat, drying time consumption and economic cost could be calculated by inputting ambient temperature, ambient relative humidity, air temperature, air volume, and initial moisture of wheat. Then the optimal operating parameters, which caused the lowest economic cost, would be obtained under different ambient conditions and initial moistures of wheat by further analysis and comparison. In order to verify the accuracy of simulation results, experimental studies of post-harvest wheat drying were performed with the self-developed 5H-2.0A box-typed static bed reversing ventilation dryer, which involved in testing and analysis of the average moisture distribution of materials in the thickness direction of wheat bed and the energy dissipation. The wheat dry bed was 40 cm in depth, with an initial average moisture content of 19.2% (wet basis). The air temperature and volume were set as 40℃ and 625 m3/ (m2· h) respectively, and the ambient average temperature and relative humidity were 26.4℃ and 62.3% respectively during the experiment. The area of drying region on horizontal plane was evenly divided into 9 units for testing moisture content of the wheat dry bed, and the dry bed in 40 cm deep on vertical plane was evenly divided into upper, middle and bottom layer. It was concluded that the partial differential equation models could be used to simulate the actual drying process of wheat reliably. The model simulation results were in consistent with the experimental results, and the correlation coefficient of average moisture content for the whole wheat bed between test value and analog value was 0.995, among which correlation coefficients for the upper, middle and bottom layer were 0.994, 0.973 and 0.998, respectively. Based on this, the change rule and mechanism of moisture and temperature distribution on wheat bed during reversing ventilating drying were analyzed. Finally, when the ambient temperature ranged from 20 to 35℃, the ambient relative humidity varied from 20% to 85%, and the average initial moisture content was 16%, 18% and 20%, respectively, the best ventilation temperature and volume, which caused the lowest cost of energy consumption, were analyzed and then determined by comparing the cost of energy consumption at different air temperature (from 40 to 50℃) and air volume (from 500 to 1000 m3/ (m2·h)). © 2015, Chinese Society of Agricultural Engineering. All right reserved.


Hu Z.,Nanjing Research Institute of Agricultural Mechanization | Wang H.,Nanjing Research Institute of Agricultural Mechanization | Wang J.,Nanjing Research Institute of Agricultural Mechanization | Hu L.,Nanjing Research Institute of Agricultural Mechanization | And 2 more authors.
Nongye Jixie Xuebao/Transactions of the Chinese Society of Agricultural Machinery | Year: 2010

In order to improve the operation performance of 4HLB2 peanut combine harvester, the impact factors including soil moisture content, harvest time, stalk clamping height, clapping frequency and amplitude of clod removing unit, rotate speed of peanut picking roller and clamping chain speed were investigated by single or double factorial experiments. The results show that soil moisture content ranging from 8% to 15% is suitable for peanut harvesting in sandy loam soil. Dropped peanut loss during clod removing increases gradually along with the delaying of harvest time. The dropped peanut loss rate is higher than 2% under the snap force of peanut root below 5N. The optimum stalk clamping height is in the range from 150mm to 200mm, keeping total loss rate and clod content less than 6% and 4%, respectively. Lower frequency and smaller amplitude of clod clapping operation contributes to smaller dropped peanut loss rate, but higher clod content, whereas, higher frequency and larger amplitude contributed to lower clod content and higher dropped peanut loss rate. The peanut loss of peanut picking operation is kept at lower level with higher picking roller speed and lower clamping chain speed. In this experiment, loss rate of peanut picking is 2.79% at 390r/min of picking roller speed and 0.5m/s of clamping chain speed.


Hu Z.,Nanjing Research Institute of Agricultural Mechanization | Wang H.,Nanjing Research Institute of Agricultural Mechanization | Peng B.,Nanjing Research Institute of Agricultural Mechanization | Chen Y.,Nanjing Research Institute of Agricultural Mechanization | And 2 more authors.
Nongye Jixie Xuebao/Transactions of the Chinese Society of Agricultural Machinery | Year: 2012

A semi-feeding peanut picking test-bed was developed to carry out the studies on optimized design and experiment on the structural and motion parameters of semi-feeding peanut picking device. Based on the motion analysis of picking process, ideal position state and parameter relationship of pods cluster during the picking section were determined to ensure that all the pods cluster could pass through the best picking areas by bottom-up and gradual-orderly mode. Influencing factors of picking frequency and strength as well as the influence on the picking performance were analyzed. On the basis of picking mechanism analysis and the experimental verification, the picking roller employed six backward-curved blades. After the multi-criteria response surface experiments, the optimized combination of structural and operational parameters were obtained as follows: the roller length was 1200 mm, the included angle between chain and roller was 7.2°, the roller diameter was 152.5 mm, roller overlap distance was 5 mm, roller rotate speed was 371 r/min, chain conveying speed was 1.025 m/s.


Hu Z.,Nanjing Research Institute of Agricultural Mechanization | Wang H.,Nanjing Research Institute of Agricultural Mechanization | Peng B.,Nanjing Research Institute of Agricultural Mechanization | Chen Y.,Nanjing Research Institute of Agricultural Mechanization | And 2 more authors.
Nongye Gongcheng Xuebao/Transactions of the Chinese Society of Agricultural Engineering | Year: 2012

In order to investigate the operation process and performance of plant lifting of 4HLB-2-type peanut combine harvester, the motion analysis of the plant lifting device was carried out to explore the influence of motion parameters and location configuration parameters of all parts on plant lifting effect, and the field experimental verification was performed subsequently. According to the motion analysis, when the design parameters of vine uprearing device obliquity was 80°, clamping chain obliquity was 35°, vine uprearing speed ratio was 1.5, chain speed ratio was 1.2 and so on, peanut plant was nearly perpendicular with the clamping chain, and the pulling force of clamping chain was nearly directed in up-vertical orientation. Based on the analysis of the peanut vine uprearing motion process, the calculation methods of the vine uprearing times and the maximum active uperaring fingers for individual peanut plant were determined, and the separation distance of uprearing fingers optimized was 150 mm. The theoretical analysis also involved the influence of the location relation of vine uprearing device, digging shovel and clamping chain on the peanut plant lifting performance. And the main location parameters in the side view of the three parts were determined. Field tests showed that the motion parameters and location configuration of all parts can meet the performance requirements of peanut plant lifting, and the practical process and status of plant lifting were in agreement with the results of theoretical analysis. This paper provides a reference for improvement of structural design and optimization of working parameters in same type device.


Wu H.,Nanjing Research Institute of Agricultural Mechanization | Hu Z.,Nanjing Research Institute of Agricultural Mechanization | Peng B.,Nanjing Research Institute of Agricultural Mechanization | Gu F.,Nanjing Research Institute of Agricultural Mechanization | And 2 more authors.
Nongye Gongcheng Xuebao/Transactions of the Chinese Society of Agricultural Engineering | Year: 2013

The sugar beet is one of the major sugar crops in China, accounting for about 17% of Chinese total sugar production. As a seasonal operation, sugar beet harvesting in China is still mainly manual work, characterized by high labor intensity, low efficiency, great harvest losses, and huge occupation of farming, all of which constraine the further development of the sugar beet industry. Mechanized harvesting is the inevitable development trend of sugar beet harvesting. The current domestic sugar beet harvesters are basically simple sectional operating machinery. Sugar beet combine harvesters are mainly imported from abroad, having high automation and intelligence and advanced performance. The domestic beet combines are still in the prototype development stage, having a great gap with the advanced foreign technology. Auto-follow row technology is one of the key features of beet combine harvesting, having great influence on machinery performance. Although domestic researchers have performed lots of studies on the automatic control of agricultural machinery, research on control systems for auto-follow harvesters is still scarce, which greatly affects the automation level and operation performance of domestic beet combine harvesters. In order to improve the automation level and reduce harvesting loss, a set of auto-follow row system for a pull-type beet combine harvester was designed by adopting hydraulic technology, sensor signal acquisition technology, and microprocessor control technology, which was based on the ridge-planting cultivation of sugar beets. The system includes a row detection mechanism, an adjustment mechanism for traction offset, a hydraulic control system, an electronic control system, and control software. The row detection mechanism detects the position of the ridge top beetroot block, converts the offsets of excavation forward locus to angle quantity, and then sends the information to the offset angle acquisition sensor. The offset angle acquisition sensor converts angle information to a digital signal and sends it to the controller. The controller handles the angle signal and outputs a control signal for the solenoid valve, through the control software, opening the hydraulic cylinder drive oil line. The hydraulic cylinder drives the traction biasing mechanism, adjusting the digging position. The angle feedback sensor installed on the traction-offset mechanism feeds back the adjusted angle signal to the controller. The controller adjusts output control signals in real time, ensuring the excavation forward locus always consistent with the beetroot block position. The entire control system is a closed-loop feedback system. The controller is a single-chip microprocessor μPD78F0525. Control software adopts Keil C language, using a fixed double dead zone control algorithm, because it increases system noise immunity, avoids frequent shocks of control action, and improves control stability. Standard signal tracking tests showed that the system had fast-response characteristics and high stability. The results of comparison experiments showed that the harvesting indexes of the beet combine were improved by employing the control system of auto-follow row, in which the loss rate of un-harvested beets, the root body fracture rate, and the root block damage rate were reduced by 2.03%, 1.48% and 2.64%, respectively. This study can provide effective reference for the development of auto-follow row systems employed in similar harvesting machinery.


Ding S.,Nanjing Research Institute of Agricultural Mechanization | Fu X.,Nanjing Research Institute of Agricultural Mechanization | Xue X.,Nanjing Research Institute of Agricultural Mechanization | Zhou L.,Nanjing Research Institute of Agricultural Mechanization | Lu X.,Nanjing Research Institute of Agricultural Mechanization
Nongye Gongcheng Xuebao/Transactions of the Chinese Society of Agricultural Engineering | Year: 2013

Plant protection is very important for high yield and quality of fruits production. A new self-propelled sprayer with low height was developed accommodating small space and poor trafficability of conventional orchards which are densely planted with dwarf plants. The power transmission system of the machine was optimized and the air supply atomization device was designed. The power transmission system distributes power separately, so the fan, pump, walking and steering device can be controlled independently. Designing of the air supply device and main technical parameters of key parts were based on theories of fluid mechanics and pesticide delivery technique applications. The R+S channel, 9 impellers, 11 guide glades was adopted. The diameter of impellers was 0.6 m and the width of guide glades was 0.1 m. The fan property was tested and the performance curve graphic was drawn. Frequency transformer, torque meter, wind velocity indicator was used and the testing ring was put 1m ahead of the air enter which was connected with a set of rams to fan pipes. The ram's diameter are 0.6 m, as same as fan's. The results showed that air volume was 2.7 m3/s meet at 1400 r/min which demands design needs. The highest total pressure efficiency is 86% at 1600 r/min. As the speed increases, total pressure efficiency dropped rapidly but the power increased. The variation trends of the air volume and air pressure are not significant. The field experiment was conducted in an apple grove which was grown with "Jinshiji " apple trees. The experiment followed strictly the quality of air-assisted orchard sprayer (NY/T 992-2006) and evaluating regulations for the operation and spraying (GB/T17997-2008). The row space was 3 m × 2 m, diameter of the tree crown was 2 m, the height of the tree was 2.5 m. Three trees were randomly selected as sample trees. The intersection points of three horizontal layers and three vertical layers of each tree were set as sample points, that is, 27 sample points totally for one tree. Water-sensitive paper card with the same size to apple leaves were put on sample points both front and rear sides receiving droplets to measure the cover ratio of droplets. The paper cards were numbered according to the sample points. Paper cards were collected after droplets got dry. Droplets cover ratio of each paper card was measured by micro camera and droplets image processing system. Results showed that the spraying coverage and droplets density increased significantly with the increase of the fan speed, spraying manipulation was conducted at the condition of 0.5 MPa spray pressure, 1400 r/min fan speed, and 1.26 m/s velocity, the spraying coverage in front and rear of the leaf was 58.76% and 19.06% inside the tree, and 69.35% and 32.66% outside the tree crown, droplets density in front and rear of the leaf was 115 and 79 droplets/cm2 inside the tree, and 105 and 96 droplets/cm2 outside the tree crown. The operation efficiency reached to 0.91 hm2/h when the proportion of auxiliary time and operation time is one to two.


Wang S.,Nanjing Research Institute of Agricultural Mechanization | Hu Z.,Nanjing Research Institute of Agricultural Mechanization | Peng B.,Nanjing Research Institute of Agricultural Mechanization | Wu H.,Nanjing Research Institute of Agricultural Mechanization | And 2 more authors.
Nongye Jixie Xuebao/Transactions of the Chinese Society for Agricultural Machinery | Year: 2013

An auto-follow row mechanism was designed. A three-dimensional model of the auto-follow row mechanism was built under the application of UG, and then imported to the mechanical system dynamics simulation software ADAMS to build a virtual prototype model. Taking beet as harvest object, the simulation of the auto-follow row movement in ADAMS/View environment was conducted by setting the model parameters, adding constraints and drive. Taking the return spring stiffness, reset spring preload and operating forward speed of the auto-follow row mechanism as influencing factors, and taking the angular velocity of the angle sensor as the objective function to characterize auto-follow row sensitivity and drain digging rate, a virtual orthogonal test of parameters was performed, which affected auto-follow row movement. A field verification test was also carried out and the results showed that the effect of the return spring stiffness was not significant. When the return spring preload force was 200 N, the forward operating speed was 1.5 m/s, and the drain dug loss rate was minimum.

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