• Journal of Biosystems Engineering
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• v.25 no.5
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• pp.369-378
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• 2000

The purpose of this study is to developed high-efficient rotary tillage system for a power tiller by improving the rotary blade. A kind of the rotary blade with single-edged blade(DS) was developed that requires lower tillage energy than conventional double-edged blade(CD) on the design theory for Japanese rotary blade. In order to find out the tillage characteristics between the single-edged blade and the double-edged blade for power tiller, experiments were performed in soil-bins which were filled up clay loam, loam and sandy loam, and then analyzed the effects of the factors such as soil texture, travelling speed, rotational speed, and tillage depth to each of the blades. And field tests were carried out to compare tillage performances of the two blades using rotary cultivator driven by conventional power tiller. The results of this study were summarized as follows; 1) On the soil bin experiment, it was found that tillage torque of the single-edged blade was less than the ones of the double-edged blade. The decreasing ratios of maximum tillage torque of the single-edged blade to the ones of the double-edged blade were 1 to 8% at clay loam, 5 to 20% at loam and 9 to 31% at sandy loam, respectively. 2) By the field tests, that the tillage performances with the single-edged blade compared with the double-edged blade was improved about 19% in field capacity, about 34% in fuel consumption, and 12.5% in soil breaking ratio. Furthermore, the fluctuation of engine speed, the variation of exhaust gas temperature, and the amount of soil clogging on the blade and straw wound on the rotary shaft showed lower values with the developed blade than the conventional blade. So, it may be concluded that tillage performance by the developed single-edged blade was improved compared with the one by the conventional double-edged blade.

• Korean Journal of Agricultural Science
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• v.48 no.4
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• pp.1027-1037
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• 2021

This study aims to evaluate the performance of an electric multi-purpose cultivator through a simulation analysis. The simulation model was developed using commercial software, Simulation X, by applying the specifications of certain parts, such as an electric motor, a battery, and so on. The input parameter of the simulation was the engine load data according to the rotary tillage level using a conventional multi-purpose cultivator. The data were collected by configuring a load measurement system, and the load cycle was developed by repeating the data collection process under the most severe conditions. The average output engine torque values of conventional multi-purpose cultivator were 10.7, 13.0, 9.4, and 11.2 Nm in the D1P1, D1P2, D2P1, and D2P2 conditions, respectively. As a result of the simulation, the maximum values of the motor torque, rotational speed, and power of the electric multi-purpose cultivator were 16.8 Nm, 2,033.3 rpm, and 3.3 kW, respectively, and the motor was driven in sections within 70, 68, and 45% of the maximum output range. The rate of decrease of the battery state of charge (SOC) level per minute was approximately 0.6%, and it was possible to supply electric power to the motor for 9,550 sec. In the future study, research to verify and improve simulation models of electric multi-purpose cultivators should be conducted.

• Journal of Biosystems Engineering
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• v.32 no.4
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• pp.215-222
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• 2007

In the study, the cone index, the cohesion and the internal friction angle of soil were measured before and after tillage in order to suggest relative improvement in soil properties by comparing the two measured values before and after tillage. The tillage methods tested in the study were five combinations of plowing and rotovating; one plow tillage operation, one plow followed by one rotary, one plow followed by two rotary, one rotary without plow and two rotary without plow. The experiments were performed in a soil bin in Sunggyunkwan Univ. and in four selected test fields in Yeoju, Seodun-Dong, Suwon (especially, two different fields) and Chungju. In general, the internal friction angle and cohesion of soil increased with the increase of soil compaction. After applying the tillage operations, the internal friction angle reduced by 14 degree and the cohesion decreased up to about $2.2N/cm^2$ on the soil bin in comparison with those before tillage. The two values, however, reduced by 9 degree and up to about $1.0N/cm^2$ on the tested fields. The CIs for all the tillage operations on the soil bin and on 4 different test fields were decreased by 800 kPa in comparison with those before tillage. The best combination of tillage operations for decreasing the CIs of soil was one plow operation followed by one rotary. The CIs for one plow operation followed by two rotary were slightly higher than that for one plow operation followed by one rotary because one plow operation followed by two rotary crushed down the soil excessively, so that the porosity of soil decreased.

• Korean Journal of Agricultural Science
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• v.11 no.2
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• pp.264-269
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• 1984

The single edged blade was efficient to reduce tilling torque requirement than the double edged blade as previous reported study. This study was carried out to find reducing effects of tilling torque requirement of single edged blade comparing to double edged one in according to wearing by tilling operation. The single and double edged rotary blades were attached on same rotary shaft, and tilling operation was done in hard glass land. The wearing weights of the blade were checked out each 3 hrs tilling operation, at same time, the tilling toruqe requirements were measured with soil bin system in laboratory. The results of the study were summarized as follows: 1. The edged blade shape was not changed during the tilling operation of the rotary blade. The single edged blade was saved 5-10% in the maximum tilling torque and 3-15% in the mean tilling torque than the double edged blade for total durable period. 2. Generally, the tilling torques according to operation were decreased until original shape was maintained, but it was increased after 12 hrs tilling operation, and the tip shape of rotary blade was changed seriously. It is noted that the tip shape of the rotary blade is another factor affecting tilling torque, it should be desirable to study on the rotary blade tip shape to reduce tilling torque requirement after changing its original shape with wearing.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.11 no.4
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• pp.51-54
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• 2012

This paper aims to design and analyze the stationary fixture type automatic rotary drilling machine and estimate the safety of the machine through simulations. Working conditions of typical rock excavating machines are mostly affected by geographical conditions on the sea, such as by the ebb and flow of the tide or high waves. Due to the size of machines, it is difficult to move and install machines. So it is necessary to develop a machine that not only can be moved and installed more easily also be operated more quickly and automatically. To validate the safety of the designed structure of the machine, static analysis has been carried out. The results of stress and deformation analysises show that the designed machine is stable and safe in hard working condition.

• Journal of Biosystems Engineering
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• v.22 no.2
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• pp.105-116
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• 1997

Using the design variables and conditions reported in the rut part of this paper, an analysis and optimum design of the tractor-rotary power driveline were carried out. The optimum design method involved 1 variable, 2 variable and multiple variable analysis performed as requested in the design process. In order to evaluate the effects of the design variables on the power transmission performance a sensitivity analysis were also conducted. the results indicated that the length and link point of the upper link, the upper hitch point of the implement master and the location of the implement input connection affect most significantly the driveline performance. The optimum design improved the performance of an exampled tractor-rotary driveline by 93% in terms of cosine ratio.

• 유체기계공업학회:학술대회논문집
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• 2004.12a
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• pp.533-539
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• 2004

The rotary compressor is widely used for the air conditioner because it is efficient and compact. In recent, the need for silent and efficient compressors is much stronger than the past. The new type muffler was invented to reduce noise level and to improve efficiency. The new type muffler that has two side discharge holes and dome shape represents much lower overall noise level, especially noise levels around 1kHz than the old type one that has one center discharge hole In acoustic spectra. Also it has higher air conditioner efficiency by lower oil discharging amount of a compressor than old type one that has rectangular shape and two side discharge holes. The noise reduction and efficiency improvement effects of the new type muffler were verified by tests for rotary compressors and air conditioners.

• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 2003.02a
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• pp.57-62
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• 2003

우리나라의 농용트랙터 농가 보급률은 2000년 현재 13.9%로 약 19만대 정도이며 연간 약 2만대 정도의 농용 트랙터가 보급되고 있다. 농작업 중 가장 동력이 크게 소요되는 경운작업은 1차 경기작업과 2차 쇄토작업으로 크게 나눌 수 있는데 근래에는 이것을 동시에 작업화하여 작업시간과 에너지 및 경비를 절감할 수 있는 로타리 경운작업만 실시하는 경향으로 발전하고 있다. (중략)

• Journal of Biosystems Engineering
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• v.42 no.1
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• pp.44-55
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• 2017

Background: Heat recovery is one of the prominent ways to save a considerable amount of conventional fossil fuel and minimize its adverse effects on the environment. The rotary heat exchanger is one of the most effective and efficient devices for heat recovery or heat exchanging purposes. It is a regenerative type of heat exchanger, which has been studied and used for many heat recovery purposes. However, regenerative thermal wheels have been mostly used as heat recovery systems in buildings. For modeling a rotary regenerator, it is very important to numerically consider all the factors involved, such as effectiveness, rotational speed, geometrical size and shape, and pressure drop (${\Delta}p$). In recent times, several researchers have actively studied the rotary heat exchangers, both theoretically and experimentally. Reviews: In this paper different advances in the numerical modeling of regenerative rotary heat exchangers in relation to fluid flow and heat transfer have been discussed. Researchers have indicated that the effectiveness of the regenerative rotary heat exchanger depends on various factors including, among many others, rotational speed, rotational period and combustion power. It is reported that with the increase of periodic rotation the deviation of theoretical results from the experimental result increases. The available literature indicates that regenerative heat exchangers are having relatively more effectiveness (60-80%), compared to other heat exchangers. It is also observed that the finite difference method and finite volume methods are mostly used for discretizing the heat transfer governing equations, under some assumptions. Research also indicates that for the effectiveness calculation the ${\varepsilon}-NTU$ method is the most popular and convenient.

• Journal of Biosystems Engineering
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• v.18 no.4
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• pp.344-350
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• 1993

The purpose of this study is to develop design equations to calculate optimum specifications and dimensions such as weight, engine horsepower, etc. of the tractor necessary to perform stable rotary tillage. The main results of this study are as follows. 1. A wheel-lug ought to receive a special resistance in downward direction which resists the lug's upward motion on wet sticky soil surface. The authors introduce a new academic name of the "lift resistance(上昇抵抗力, 상승저항력)" for such a force which resists retraction of a wheel lug from the soil in the upward trochoidal motion. This force is composed of the frictional force acting on the trailing and the leading lug side, and the "perpendicular adhesion(鉛直付着力, 연직부착력)" acting on the lug face and the undertread face on adhesive soil. 2. The "lift resistance ratio(上昇抵抗力係數, 상승저항력계수)" and the "perpendicular adhesion ratio(鉛直付着力係數, 연직부착력계수)" were defined, which are something similar to the definition of the motion resistance ratio, the traction coefficient, etc. 3. The design equation of the optimum weight of a rotary tiller mounted on the tractor derived by calaulating the forces acting on the rotary blades. 4. The design equations to calculate optimum specifications and dimensions such as weight, engine horsepower, etc. of the tractor necessary to perform stable rotary tillage were derived. It becomes clear that the optimum weight of a rotary tiller and a tractor can be estimated in planning design by means of putting about 21 design factors of the target into the equation. These equations are useful for planning design to estimate the optimum dimensions and specifications of a rotary tiller as well as a tractor by the use of known and/or unknown design parameters.