• Transactions of the Korean Society of Automotive Engineers
• /
• v.20 no.5
• /
• pp.36-43
• /
• 2012

In this work the mixing and flow characteristics of a vane-type static mixer were investigated numerically for the reduction of NOx in the SCR-system of the diesel engines. The mixer was located in the 57 times pipe diameter away from the inlet. The analysis were performed by changing such various parameters as vane shape, angles, blockage ratio and location of the vane. The flow structure through the mixer was characterized by uniformity index and pressure drop. The results show that uniformity index and pressure coefficient are substantially influenced by the vane shape, angle, blockage ratio and position of the vane of the mixer.

• 유체기계공업학회:학술대회논문집
• /
• 1999.12a
• /
• pp.55-60
• /
• 1999

A centrifugal compressor was tested with three different diffusers with plate vanes. The vane inlet angle was varied from 15 to 30 dog. The higher static pressure rises are obtained with lower vane stagger angle. In the stable region the static pressure field in vaneless space is very sensitive to flow rate. The impeller has a stabilizing effect over the whole stable operating range. The diffuser has a stabilizing effect at high flow rate but is destabilizing at low flow rate.

• 제어로봇시스템학회:학술대회논문집
• /
• 2004.08a
• /
• pp.1211-1214
• /
• 2004

In this paper, we propose to use variable inlet guide vane as a means of active surge control to solve above problems. There is some advantage. For example, since the inlet guide vanes are already present in POSCO, no additional actuation device is required. We can collect all data easily which is related to the test and can simulate new model using our compressors. We can obtain the result that blow-off valve is opened less 5% and can operate air compressor automatically and more efficiently. Through a simulation example, the effectiveness of the proposed schemes is illustrated.

• Transactions of the Korean Society of Mechanical Engineers B
• /
• v.40 no.8
• /
• pp.519-525
• /
• 2016

In a pump, from the performance point of view, it is very important to minimize the shock loss at the inlet of the rotor blades. In this study, the effects of shape and install angle of the inlet guide on the performance of an axial-flow pump are numerically simulated using commercial CFD code, Ansys CFX. Finally, to obtain the optimized shape of the vanes and the install angle of the vanes in the inlet guide under given operating conditions, optimization analysis is conducted using Analysis design exploration based on response surface optimization.

• Proceedings of the Korean Society of Propulsion Engineers Conference
• /
• 2011.11a
• /
• pp.182-186
• /
• 2011

Ejector-diffuser system has long been used in many diverse fields of engineering applications and it has advantages over other fluid machinery, because of no moving parts and structural simplicity. This system makes use of high-pressure primary stream to entrain the low-pressure secondary stream through pure shear actions between two streams. In general, the flow field in the ejector-diffuser system is highly complicated due to turbulent mixing, compressibility effects and sometimes flow unsteadiness. A fatal drawback of the ejector system is in its low efficiency. Many works have been done to improve the performance of the ejector system, but not yet satisfactory, compared with that of other fluid machinery. In the present study, a mixing guide vane was installed at the inlet of the secondary stream for the purpose of the performance improvement of the ejector system. A CFD method has been applied to simulate the supersonic flows inside the ejector-diffuser system. The present results obtained were validated with existing experimental data. The mixing guide vane effects are discussed in terms of the entrainment ratio, total pressure loss as well as pressure recovery.

• The KSFM Journal of Fluid Machinery
• /
• v.10 no.1 s.40
• /
• pp.34-40
• /
• 2007

In this study, the characteristic of a vane pump of automotive power steering system is numerically analyzed. The vane pump changes the energy level of operation fluid by converting mechanical input power to hydraulic output. To simulate this mechanism, moving mesh technique is adopted. As a result, the flow rate and pressure are obtained by numerical analysis. The flow rate agrees well with the experimental data. Moreover, the variation and oscillation of the pressure around the rotating vane are observed. As a result of flow characteristics, The difference of pressure between both side of vane tip causes the back flow into the rotor. As the rotational velocity increases, the flow rate at the outlet and the pressure in the vane tip rises with higher amplitude of oscillation. In order to reducing the oscillation, the design of devices for decreasing the cross-area of the outlet part and returning the flow from the outlet to the inlet is required.

• Journal of the Korean Society of Propulsion Engineers
• /
• v.19 no.5
• /
• pp.52-61
• /
• 2015

This paper performed a numerical study to analyse the transient performance behavior of a turbofan engine with variable inlet guide vane (IGV) and bleed air schedules. The low bypass ratio mixed flow turbofan engine was considered in this study. For modeling the compressor performance with IGV, the performance maps were generated by using a one-dimensional meanline analysis and feed to the engine simulation program. The IGV and bleed air according to the rotating speed were scheduled to satisfy 10% of surge margin at steady-state condition. The transient engine performance analysis was conducted with the schedules. The engine with IGV schedule showed a higher surge margin and lower turbine inlet temperature than the engine with bleed air schedule during the transient period.

• International Journal of Fluid Machinery and Systems
• /
• v.4 no.4
• /
• pp.360-366
• /
• 2011

Thin circular-arc blade is often used as a guide vane, a deflecting vane, or a rotating blade of low pressure axial-flow turbomachine because of its easy manufacture. Ordinary design of the blade elements of these machines is done by use of the carpet diagrams for a cascade of circular-arc blades. However, the application of the carpet diagrams is limited to relatively low cambered blade operating under optimum inlet flow conditions. In order to extend the applicable range, additional design data is necessary. Computational fluid dynamics (CFD) is a promising method to get these data. In this paper, two-dimensonal cascade performances of circular-arc blade are widely analyzed with CFD. The results have been compared with the results of experiment and potential theory, and useful information has been obtained. Turning angle and total pressure loss coefficients are satisfactorily predicted for lowly cambered blade. For high camber angle of $67^{\circ}$, the CFD results agree with experiment for the angle of attack less than that for shockless inlet condition.

• Journal of Environmental Science International
• /
• v.29 no.5
• /
• pp.457-468
• /
• 2020

With continuous industrial development, the types, and amount of particulate matter (PM) have been increasing. Since 2018, environmental standards regarding PM have become more stringent. Pulse air jet bag filters are suitable for PM under the 20 ㎛ and, can function regardless of size, concentration and type. Filtration velocity and shape are important factors in the operation and design of the pulse air jet bag filters however, few established studies support this theory. In this research, numerical simulations were conducted based on experimental values and, several methods were employed for minimizing the pressure drop. In the pilot system, as the inlet duct velocity was faster than 19 m/sec, flow was not distributed equally and, re-entrainment occurred due to the hopper directional vortex. The multi-inlet system decelerated the hopper directional vortex by 25 ~ 30%, thereby decreasing total pressure drop by 6.6 ~ 14.7%. The guide vane system blocked the hopper directional vortex, which resulted optimal vane angle of 53°. The total pressure of the guide vane system increased by 0.5 ~ 3% at 1.5 m/min conditions. However, the filtration pressure drop decreased by 4.8 ~ 12.3% in all conditions, thereby reducing the operating cost of filter bags.

• International Journal of Fluid Machinery and Systems
• /
• v.9 no.2
• /
• pp.137-142
• /
• 2016

Variable Geometry System (VGS) is widely applied to the nozzle vane for the radial inflow turbine constituting automotive turbochargers for the purpose of optimizing the power output at each operating condition. In order to improve the performance of radial turbines with VGS, it is necessary to clarify the influences of the setting angle of nozzle vane on the internal flow of radial turbine. However, the experimental measurements are considered to be difficult for the flow in radial turbines because of the small size and the high rotational speed. In the present study, the numerical calculations were carried out for the flow in the radial turbine at three operating conditions by applying the corresponding nozzle vane exit angles, which were set up in the experimental study, as the inlet boundary condition. The numerical results revealed the characteristic flow behaviors at each operating condition.