This paper proposes the armored combat bulldozer, essential for amphibious tasks, requires water ingress prevention and submersion capabilities, typically addressed by a centrifugal pump. This study aims to boost the bulldozer's drainage pump efficiency by replacing the traditional aluminum 3-blade impeller with one made of ASA material using 3D printing. Analysis via ANSYS Fluent revealed that the 5-blade impeller increased discharge volume by 19.31% and efficiency by 6.07%, while the 6-blade variant saw a 27.07% increase in discharge volume and 8.81% efficiency improvement. Further scrutiny with ANSYS Static Structure ensured the new impellers' structural integrity and robustness under extreme conditions. This research confirms the potential of 3D printing in enhancing military equipment, demonstrating significant improvements in pump performance and opening paths for advanced manufacturing techniques to meet the demanding needs of combat vehicles.

In this study, numerical analysis is conducted to understand the flow characteristics of the radial impeller with the design parameters such as the blade shape and position using the ANSYS Fluent software. The shape of blade is divided into two types, a backward curved blade and an airfoil forward curved blade. To examine the fundamental flow characteristics near the blades, a rectangular flow field is modeled and analyzed. On the other hand, for the impeller rotation analysis, the simulation is performed by modeling the rotational region separately. As a result, the airfoil forward curved blade shows higher outlet flow rate than the backward curved blade. In addition, as the depth of the impeller and the attachment angle of blade increase, the higher flow rate appears.

As modern industries are highly being developed, it is required that mechanical parts have to be manufactured with a high precision. In order to have precise parts, error-free designs have to be done before manufacturing with accuracy. For this intention being fulfilled, a mechanical analysis is essential for design proof. Nowadays, FEM simulation is a popular tool for verifying a machine design. In this paper, an impeller, being utilized in a compressor or an oil mixer as an actuator, is studied for an evaluation. The purpose of this study is to present a safety of an impeller for a proof of its mechanical stability. A static analysis for stress, strain, and deformation within a regular usage is examined. This simulation test shows 357.26×106 Pa for maximum equivalent stress and 0.207mm for total deformation. A fatigue test is carried to provide durability and its result shows that minimum safety factor is 3.2889, which guarantees that it runs without a fatigue failure in 106 cycles. The natural frequencies for the impeller is ranged from 228.09Hz to 1,253.6Hz for the 1st to the 6th mode. Total deformations at these natural frequencies are shown from 6.84mm to 12.631mm. Furthermore, Campbell diagram reveals that a critical speed is not found throughout regular rotational speeds. From the test results for the analysis, this paper concludes that the suggested impeller is proved for its mechanical safety and good to utilize at industries.

In this study, a newly developed agitator with hydrofoil impeller applied to actual biological process in advanced wastewater treatment plant was evaluated. Several series of experiments were conducted in two different wastewater treatment plants where actual problems have been occurred such as the production of scums and sludge settling. For more effective evaluation, computational fluid dynamics (CFD) and measurements of MLSS (Mixed Liquor Suspended Solids) and DO (Dissolved Oxygen) were used with other measuring equipments. After the installation of one unit of vertical hydrofoil agitator in plant A, scum and sludge settling problems were solved and more than seventy percent of operational energy was saved. In case of plant B, there were three cells of each anoxic and anaerobic tanks, and each cell had one unit of submersible horizontal agitator. After the integration of three cells to one cell in each tank, and installation of one vertical hydrofoil agitator per tank, all the problems caused by improper mixing were solved and more than eighty percent of operational energy was found to be saved. Simple change of agitator applied to biological process in wastewater treatment plant was proved to be essential to eliminate scum and sludge settling problems and to save input energy.

For the purpose of the enhancement of the air conditioner performance and fuel effciency, several cases of centrifugal impeller for passenger car air conditioner have been numerically analyzed by changing central angle of blades and length of outlet for shape optimization of the impeller. Commercial CFD program Fluent 6.3.26 has been used to compute velocity, temperature, pressure and turbulence intensity that can lead numerous results. The central angles of two blades and three cases of outlet length led 4～12% and 3.5～6.4% differences of velocity and flow rate, respectively. The velocity distribution near the blade surface was axisymmetric and had a maximum value of 22.19 m/s and velocity of the vertical direction of the impeller showed linear increase with horizontal direction. At case 3 of oultet length, there existed a a minimum pressure value of -133320 Pa.

곡면가공에서 5축 가공은 복잡한 형상의 공작물에 대한 가공의 필요성이 증대되면서 3축가공보다 자유곡면 가공을 위한 시도와 연구가 활발히 이루어지고 있으나 가공 시 충돌과 간섭의 문제를 해결해야하는 어려움으로 공구경로 생성에 많은 문제점을 내포하고 있다. 이러한 문제를 해결하고자 최근에는 다양한 5축 CAD/CAM Software가 개발 되었고 이를 활용하는 사례가 늘어나고 있다. 본 논문에서는 자유곡면으로 이루어진 대표적인 형상인 Impeller의 복잡한 형상을 CAD Software를 이용하여 모델링 하였고, CAM Software로 공구 경로를 생성 및 검증하였으며 5축 가공기로 직접 가공하였다.

곡면가공에서 5축 가공은 복잡한 형상의 공작물에 대한 가공의 필요성이 증대되면서 3축가공보다 자유곡면 가공을 위한 시도와 연구가 활발히 이루어지고 있으나 가공시 충돌과 간섭의 문제를 해결해야하는 어려움으로 공구경로 생성에 많은 문제점을 내포하고 있다. 이러한 문제를 해결하고자 최근에는 다양한 5축 CAD/CAM S/W가 개발 되었고 이를 활용하는 사례가 늘어나고 있다. Impeller의 곡면의 형상에 따라 터보 기계의 효율이 크게 좌우 되므로 고 정밀가공이 요구된다. 고 정밀가공을 위해 impeller의 CAD modeling과 공구경로생성 및 검증에 관한 연구가 필수적이다. 본 연구에서는 자유곡면으로 이루어진 impeller의 복잡한 형상을 상용 S/W를 이용하여 모델링하고 곡면가공을 위한 공구경로를 생성한다. 생성된 공구경로는 충돌 및 간섭의 유무를 확인하기 위해 Graphic simulation S/W를 이용하여 이상 유무를 검증하고 이를 수정한다.

Inline mixer, mixing device combined mechanical and hydraulic mixing, has been demonstrated many times to be effective in mixing process for coagulation. But most of inline mixer are difficult to utilize in relevant domestic industry since it is a foreign technology. So the development of domestic inline mixer is strongly needed. In this study, we compared mixing characteristics through computational fluid dynamics(CFD) analysis with different shape of impeller for the development of domestic inline mixer. The shape of the flow field by velocity vectors and the concentration distribution of injected coagulant were analyzed for comparison of the results. We chose two shapes of impeller(plate and screw), the CFD analysis for them was conducted to simulate actual field conditions. The screw-shaped impeller showed more well-mixing characteristics than the plate-shaped impeller from the results. On the other hand, short-circuiting flow could occur when the shape of impeller was plate.

In this paper, a wall climbing robot, called LAVAR, is developed, which is using an impeller for adhering. The adhesion mechanism of the robot consists of an impeller and two-layered suction seals which provide sufficient adhesion force for the robot body on the non smooth vertical wall and horizontal ceiling. The robot uses two driving-wheels and one ball-caster to maneuver the wall surface. A suspension mechanism is also used to overcome the obstacles on the wall surface. For its design, the whole adhering mechanism is analyzed and the control system is built up based on this analysis. The performances of the robot are experimentally verified on the vertical and horizontal flat surfaces.