Papers by Keyword: PIV

Paper TitlePage

Authors: Guan Lei Jiang, Ming Wen, Ji Fei Ye, Wen Tang Wu
Abstract: A combined measurement method with PIV and schlieren technology is described in this article. The velocity field and the shock wave structure can be obtained simultaneously with this combined measurement method by a synchronous time controller and the post-processing. The color schlieren can capture the instantaneous image effectively and clearly, while the PIV can calculate the time average velocity field and put out with the visual image. Both of them are ripe technologies, they can setup easily and even get some commercial groupwares. In this article, this combined measurement method study the under expanded supersonic jet successfully. Not only limit in the under expanded supersonic jet, this combined measurement method also can apply in the other supersonic flow. They are complementary advantaged to the investigation of supersonic flow.
Authors: Charles Adam Uleh, Jian Yong Zhang, Dong Lai Xu, Ian French
Abstract: This paper introduces a prototype multiphase flow metering system, named Uletech, for multiphase flow measurement. The Uletech Multiphase Flow Meter (UMFM) is based on the combination of particle recognition and the use of Laser Imaging Technology in the form of Particle Imaging Velocimetry (PIV). PIV uses tracer particles which follow the gas or liquid phase. The high resolution digital laser cameras identify/recognize all the different sizes of particle (gas, oil and water) in a multiphase flow. The cameras have sufficiently high resolutions (pixel size) to "see" the tracer particles. The prevailing conditions of high pressure and temperature of the flow regimes makes actual measurement a great challenge. The velocity differences between phases (hold up and slip) means unless the velocities of individual phases and concentrations are known, the true flow rate is practically impossible to obtain. The system comprised of two cameras, laser source, optical arrangement, computer data acquisition system, synchronizer and MATLAB based software. An algorithm that correlates the cameras view to the volume within the pipe has been developed through this research. The computer acquires image signals from the upstream and/or downstream cameras, and carries out the calculation of cross correlation between the two image frames so that the velocity of each pixel can be found. A Gas Liquid Chromatograph (GLC) provides the composition (concentration) of the gas and the liquid hydrocarbon (HC). The product of phase velocity and phase concentration provides the flow rate of the individual phase. This work provides theoretical analysis and experimental validations, and discusses the advantages of the system and its further development.
Authors: Lian Feng Xu, Gang Chen
Abstract: Based on the thoroughly analysis of two conventional PIV algorithm, a new velocity extracting methods called Pre-estimate Searching Algorithm(PESA) is presented in this paper which combines the superiorities of the two conventional PIV algorithms. And the realization procedure of this new algorithm is provided also. Both the synthetic images and real PIV images experiments show that the new algorithm has the advantage of high accuracy and fast computing speed.
Authors: Bukhari Manshoor, Afifah Yusof, Suraya Laily, Izzuddin Zaman, Amir Khalid
Abstract: The stirred tank is widely used in many industries to obtain the desired type of fluid mixing. In the context of mixing process, two different fluids and have a different properties will mix in a single equipment to produce another fluid with a new property. In this research, a new approach of stirred tank which is containing a new design of baffles and impellers was proposed for fluid mixing. The new design of baffles and impellers that proposed here are used a fractal pattern for both parts in the stirred tank. Implementing a fractal pattern for baffles and impellers in stirred tank believe will influence the flow characteristic inside the stirred tank, hence will improve a mixing performance. In order to investigate the kinds of flow properties, a Particle Image Velocimetry (PIV) technique with 1 μm seeding particle was used. Four configurations were tested which are normal baffles and normal impellers, normal baffles and fractal impellers, fractal baffles and normal impellers, and the last configuration is fractal baffles and fractal impellers. In this study, dual Rushton impellers with 4 blades were used with the configurations mentioned. The result shows the significant flow field capture by PIV measurement on each configuration. By using fractal impeller some vortex are shown in the tank and high velocity vector on flow field compare with normal impeller while normal baffles gives high velocity vector depends on the configuration were used. From the results, it was showed that the fractal design can give a certain level of mixing efficiency in stirred tank. The PIV technique also gives good flow visualization in order to determine the flow pattern in stirred tank with a new concept of baffles and impellers.
Authors: Xuan Xiong, Xiao Ming Ye, Kai Wang
Abstract: A wind tunnel experiment is carried out employing 2D-PIV technique to visualize the qualitative flow field and to obtain the quantitative velocity profile respectively in the wake of 1 Hz pitching oscillating airfoil of 6 degrees amplitude. In order to validate the experiment for future’s study, the experimental velocity data are compared to relative CFD ones. The CFD results are obtained from a code called Map Flow that is able to deal with the flow around pitching and plunging oscillating airfoil. From the vortices maps it is shown that the experimental results and CFD ones are well compared with respect to the size and the shape of the vortices patterns. Quantitatively, the differences between experiment and CFD with respect to the velocity profile are acceptable.
Authors: Cheol Woo Park, In Je Baek, Jong Hwan Yoon
Abstract: In the present study, the flow structure inside the refrigerating compartment of a scaleddown display cooler model was investigated experimentally using the particle image velocimetry (PIV) method, which is a reliable velocity field measurement technique. In addition, we also carried out flow visualization and computer simulations regarding the movements of thermo-fluid inside a display cooler. As a result, the velocity field measurement shows a large scale vortical flow structure inside the refrigerating compartment due to the entrained flow, thus penetrating a base plate through the open inlet gap.
Authors: Ya Dong Gong, H. Li, Guang Qi Cai
Abstract: There’s a systemic exoteric analysis and experiment study about the distribution of Ultra-speed grinding airflow field and influence factors in this paper and lots of experiments has been done in different conditions by the method of PIV (particle image velocity). A great deal of data has been gathered and the method dealing with it by using the software such as FlowMap, Tecplot and Matlab has been brought forward. Experiment and measure have been done under different conditions and lots of experiment data and results have been obtained. Many kinds of general rules influenced by factors on Ultra-speed grinding airflow field by the analysis of the experiment results, for the purpose of supporting the base of study for the effective supply of cooling and lubrication liquid.
Authors: Gan Guo Dong, Ming Zhang, Li Jun Yang, Feng Wu
Abstract: The characteristics of flow field in the KYF-0.2 flotation cell are studied by CFD, and PIV test is also carried out to verify CFD simulation results. CFD simulation results show that there is a vortex near the slurry-ward surface of impeller blades in the direction against the rotation direction, there appears the maximum velocity which is higher than the speed at blade tips. Both PIV measuring results and CFD simulation results indicate that high velocity region appears near the exterior of stator blades,where the velocity value is about 1.5 m/s. Comparison between CFD and PIV show that there are good consistency in velocity change trend and velocity value.
Authors: Han Seo Ko, Yong Jae Kim, Oh Chae Kwon, Koji Okamoto
Abstract: Velocity and density distributions of a high-speed and initial CO2 jet flow have been analyzed simultaneously by a developed three-dimensional digital speckle tomography and a particle image velocimetry (PIV). Three high-speed cameras have been used for the tomography and the PIV since a shape of a nozzle for the jet flow is asymmetric and the initial flow is fast and unsteady. The speckle movements between no flow and CO2 jet flow have been obtained by a cross-correlation tracking method so that those distances can be transferred to deflection angles of laser rays for density gradients. The three-dimensional density fields for the high-speed CO2 jet flow have been reconstructed from the deflection angles by the real-time tomography method, and the two-dimensional velocity fields have been calculated by the PIV method simultaneously.
Authors: Jun Wang, Guang Sheng Du, Yong Hui Liu
Abstract: In order to get the situation of transitional flow in tube, we tested the fluid field by PIV experiment and acquired the velocity distribution of the flow field at different Reynolds number (Re=2400 and Re=3000). At the same time the structure and characteristics of the flow field were obtained. The experimental result shows that the change of axial velocity in boundary layer is not obvious at low Reynolds number, the fluctuation of axial velocity appears and normal speed changes a little in mainstream area. With the increase of Reynolds number the axial velocity both in boundary layer and mainstream area change obviously, pulsation of the normal speed increases, the state of fluid flow gradually evolves from laminar to transitional flow.
Showing 1 to 10 of 56 Paper Titles