Papers by Keyword: Air Flow

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Authors: Xiao Xing, Guo Ming Ye
Abstract: To investigate the effect of air flow in an pneumatic splicer on splicing performance, a computational fluid dynamics (CFD) model has been developed to simulate the air flow characteristics in an splicing chamber. Three-dimensional numerical simulation is conducted and standard K-ε turbulence model is used. Velocity distributions in the chamber are presented and analyzed. The computational results show that the velocities in the chamber are transonic. The air flows in the chamber are two swirling flows with opposite directions. This work also shows that CFD technique can provide a better understanding of the behavior of the high speed air flow in the air splicing chamber.
Authors: Shao Wen Shang, He Feng Wang, Xing Yu Lu
Abstract: The STAR-CCM+ technology is also used to analyze the location and number of vents in hull coating plant in the case of constant air volume. By means of numerical simulation and mathematical model theory, this paper makes a comparison of air distribution in the working area of this plant, and found the interior velocity and temperature field vary with different location and number of vents. Specifically speaking, the lower position and improper number of vents can lead to unevenness of the internal thermal environment and imbalance of wind speed in the working area. This study provides simulated basis and technical references for the better coating operations in suitable environment, which is significant for putting forward the improvement, optimizing the quality of the coating operation and saving energy.
Authors: Muhammad Miftahul Munir, Muhammad Sainal Abidin, Abdul Rajak, Khairurrijal
Abstract: An airflow control system is one of important parts in the scanning mobility particle sizers system (SMPS) used in the field of aerosol and air filtration. In this paper, the air flow control system that consists of an air filter, a blower, an air flow sensor, a controller, and a computer are reported. A flow rate adjustment was performed by varying the rotation speed of the blower using a pulse width modulation (PWM) technique. The air flow sensor capable of measuring flow rate up to 20 liters / min was used to measure the air flow rate. In order to keep at a certain value of the flow rate, a proportional-integral-derivative (PID) control action was employed in which PID controller were manually tune. The results showed that the desired value of flow rate was quickly achieved with little overshoot was observed in the system output.
Authors: Zhao Cheng Yuan, Fu Quan Zhao, Hai Bo Chen, Jia Yi Ma
Abstract: This paper optimized the design of the cooling fans of a light-duty diesel engine through numerical simulation. Using Fluent as a platform, a detailed Computational fluid dynamics (CFD) model was developed to simulate both the aerodynamic and the acoustics performance. The model developed was validated against experimental data obtained in this research. The validated model was then used to optimize the design of the cooling fan aiming to minimize the operation noise. With the guarantee of cooling performances, the aerodynamic noise of the two fans has been successfully reduced.
Authors: Thongchai Pongtaveesap, Surapong Chirarattananon, Robert H.B. Exell, Pipat Chaiwiwatworakul
Abstract: This paper reports results of an experimental and theoretical study of the air flow in a vertical stack driven by thermal buoyancy and induced by surrounding wind. Tubular stacks with water jacket were constructed for experiments. To investigate the effect of the buoyancy force on the air flow, hot water was circulated through the stack jacket each experimental case with a different temperature. The effect due to the surrounding wind was studied using a wind tunnel to produce wind at different velocities. In this study, a simple model was developed to characterize the air flow caused by the effects. From the experimental validation, it was found that the model can predict well the volumetric rate of the air flow in the stack.
Authors: Juraj Kralik, Olga Hubova, Lenka Konecna
Abstract: Turbulence is a flow regime characterized by chaotic property changes. Randomness, fluctuations, vorticity and large Reynolds number (Re) are the basic characteristics of turbulent flows. In this contribution is Computer Fluid Dynamic simulation of air-flow over an obstacle in shape of “quarter-circular” object compared to the data from previous work. This comparison is focused on mean values of pressure in 16 selected points at different elevations. k-ω turbulence model performed well (convergence, time, CPU) and the overall error is 13.61 %.
Authors: Xue Shuai Zhu, Lu Bin Wei, Yan Wang
Abstract: The bed stiffness and install angle of the separator were determined by experiment. The high stiffness distributor with 6.5° reverse angle is suitable. Heavy product conveying velocity and efficiency were investigated at various air flows and throwing indexes. The results show air flow and throwing index have significant effect on velocity and efficiency in the conveying. When the conveying time was 20s, with the increasing of air flow and throwing index, the velocity and efficiency improved accordingly. Accordingly, when the conveying time was up to 40s, the efficiency tended to be stable and was above 90%.
Authors: Rosdi Ab Rahman, Masiri Kaamin, Amir Khan Suwandi, Mohd Jahaya Kesot, Norah Mohd Zan
Abstract: Most traditional village houses uses corrugated zinc roofing due to economic reason. Thermal discomfort will result as zinc is a highly heat absorbing material. The space under the zinc covering will experience significant temperature increase proportional to the amount of supplied heat from sunlight, and this will further be aggravated if the ventilation is poor. The purpose of this study is to determine an alternative method to lower the temperature inside a zinc covered house. The proposed method is by splashing water throughout the area of the zinc roofing, where heat exchange process will occur upon contact. The process will dissipate heat from the zinc but will increase the water temperature. Heated water will then free fall by gravity into a tank through perforated tube with very fine aperture, as water droplet. By the same heat transfer process, ambient air will lower the water temperature, which will be recirculation back to the roof. To facilitate higher rate of water cooling, fan will be provided. The tests show the system was able to lower the temperature of the zinc covered house, and can reduce cost of cooling, thus suitable for low income rural population in Malaysia.
Authors: Pakornwit Padtha, Kiatfa Tangchaichit
Abstract: The spindle motor in a hard disk drive spins at a high rotational speed. These rotations generate air flow and thermal stress. Air flow is induced by the surface roughness of the media that is moving at a high speed through air. This air passes over the surface of many parts in the drive, including the media. Thermal stress is generated by heat in the parts, e.g. voice coil motor, pre-amplifier, slider pole tips, which are heated by electric power and by the spinning of the spindle motor. The air flow and thermal stress cause a change in the media shape called deformation.Simulation results show the trend of deformation has more bending when the slider moves outward from the media axis. The pressure acted more on the underside than on the upper side which caused the media to bend up to the top cover side of hard disk drive. The maximum deformation, 15 μm, occurred at the rim of media while the distance between the media and the slider is 30 μm; thus they did not contact each other.
Authors: Aleš Rubina, Petr Blasinski, Lukáš Frič
Abstract: The main requirements of designing the internal microclimate in swimming pool halls include removing evaporating water vapor and trichloramine (NCL3) from occurrence area of swimmers. As it is apparent from the differential equation of the mass transfer over the water surface, so with increasing speed above the water level there is increasing evaporation of water vapor at the same time. This is undesirable in view of the requirement to maintaining humidity below the upper limit of recommended limits. The article aims to point out the problem with the releasing trichloramines from the water surface and thus point to a potential increase in water vapor evaporated from the water.
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