http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
- 中文 을 입력하시려면 zhongwen을 입력하시고 space를누르시면됩니다.
- 北京 을 입력하시려면 beijing을 입력하시고 space를 누르시면 됩니다.
RISS 인기검색어
- 검색키워드
- 저자 : Reza Alidoost Dafsari(레자알리두스트다프사리) (검색결과 3 건)
- 무료
- 기관 내 무료
- 유료
-
Effect of Fuel Temperature on the Drop Size Distribution Function
Reza Alidoost Dafsari(레자알리두스트다프사리),Shahnaz Rezaee(샤나즈 레자이),Foad Vashahi(포아드 바샤이),Jeekeun Lee(이지근) 대한기계학회 2020 대한기계학회 춘추학술대회 Vol.2020 No.8
The spray structure and drop size distribution issuing from industrial nozzles are important for their application. In gas turbine combustion the uniformity and spatial distribution of the swirl spray initiates the combustion efficiency and product control. This study investigates the effect of injection pressure and physical properties of a commercial jet fuel (JET-A1) in a wide range with controlling the fuel temperature on the spatial structure of the spray. Furthermore, multiple droplet distribution functions suggested in the literature were examined to find the best applicable fit. Spray structure and droplet size measurement were carried out by applying laser diagnostic methods namely phase Doppler anemometry and Mie-scattering imaging method. The results showed with increasing both injection pressure and the fuel temperature and accordingly the decreasing the fuel viscosity, surface tension and density, enhances spray cone angle and atomization quality. Both studied parameters decreased the breakup length and consequently spray mean droplet size while widened the spray cone angle. Moreover, an in-depth attempt was made to find the accordance of q value of Rosin-Rammler distribution function to fuel temperature.
-
Reza Alidoost Dafsari(레자알리두스트다프사리),Xuesong Bai(백설송),Seunghwa Yu(유승화),Jeekeun Lee(이지근) 대한기계학회 2020 대한기계학회 춘추학술대회 Vol.2020 No.8
With the increasing application of drones in multiple industries, it is essential to understand the flow structure by the movement of the rotor blade. The current study exhibits the downwash flow structure and velocity distribution of an in-house designed and manufactured rotor blade for the agricultural application. The purpose of this drone is to carry pesticide sprayer nozzles in the farm. The downwash flow caused by the rotation of the blades affect the spray structure and gives raise to the air-liquid interaction of the issuing droplets. Therefore, understanding the physics of the resulting flow is the main objective of this study. The flow velocity distribution and turbulence characteristics were measured in a dense 3D grid using a Dantec Hot-wire anemometer. The measured values were then reconstructed and illustrated as a flow field to analyze the effect of the rotational speed of the rotor (RPM) on the downwash flow in various axial levels below the rotor blade. The flow behavior was shown using physical indicators such as mean and fluctuated velocity components, turbulence, and Reynolds stress in 2D and 3D coordinates. The results of this study initially show the general velocity distribution structure and furthermore, how increasing the rotational speed increases the velocity components and turbulent intensity and the significance of this decays further downstream from the rotor blade.
-
Drift Potential of Agricultural Spray caused by Downwash Flow of Sprayer Drone
Reza Alidoost Dafsari(레자알리두스트다프사리),Xuesong Bai(백설송),Seunghwa Yu(유승화),Jeekeun Lee(이지근) 대한기계학회 2020 대한기계학회 춘추학술대회 Vol.2020 No.8
Controlling the spray drift is of high environmental demands to protect surface water and soil from chemical contamination. Agricultural drones are being increasingly used as a target spraying method with the aim of carrying pesticide atomizers on the farm to control the chemical drifts. However, the downwash flow of the rotor blade affects the spray structure. The axial component of velocity gives rise to the droplet acceleration and the radial and tangential velocity components cause side drift to the spray droplets. The rotational speed of the rotor blade as the main parameter to identify the downwash flow intensity and the radial position of the nozzle below the rotor as the spatial characteristic can control this effect. Magnification of both mentioned parameters is the main objective of this study. The spray structure influenced by controlling the test parameters was captured with the Mie-scattering imaging method using a CCD camera synchronized to a Nd:Yag laser. The captured images were then post-processed. The results were analyzed qualitatively and quantitatively to show the effect of test parameters on the magnitude of the drift. The operational conditions were tested for various agricultural nozzles producing a range of droplet size from fine to coarse to cover the role of nozzle performance in drift potential. Large droplet generating nozzles showed to have essentially better drift resistance compared to finer spray. The rotational speed of the rotor blade (RPM) increases the drift and has to be considered as a design parameter since it’s dependent on the weight of the drone. The radial position of the nozzle from the center of the blade was found to have a great impact on the matter. To minimize the drift occurrence, the ideal position of the nozzle is when the center of the nozzle coincides radially with the center of the blade.
연관 검색어 추천
이 검색어로 많이 본 자료
활용도 높은 자료
