Proceedings of The 7th International Conference on Innovation in Science and Technology
The analyze of used particles in PIV technique and their generation systems in order to field current seeding
Mohamadreza soufivand, Shadi Ghafouri, Mohamad Hojaji and saeed tolani
In PIV technique, it is indispensable to have a visible field current in order to achieve quantitative data. For this use, the fluid should be invested by some particles. The selection of material and the size of such particles depends on, flow regime, the kind and the phase of the fluid, power and the kind of laser and the pixel of the camera. In PIV, particles should be distributed with homogeneous size and they should have a very high generation rate. It is noteworthy to mention that, the design of investment instrument depends on the kind of the experiment. The objective of this paper is to analyse and introduce seed investment particles in PIV technique. In Addition, considering the wide application of smoke and oil particles, their generation systems will be analysed. From the results of this study, it should be remarked that, oil has higher shine in comparison with water, when they are expositing to the sun. As the viscosity of the oil decreases, the out coming particle volume increases. It should be considered that, the use of industrial oils should be limited-especially in tunnels having no access to exterior space- because they are poisonous and will cause respiratory problems in man. The increase of outcome volume particles ensues from the increase in flow rate. The augmentation of inlet pressure of nozzles causes an augmentation in velocity. As a result, the momentum will enhance. Keeping it in mind, the velocity should be controlled to eliminate the possibility of turbulence and shear stress caused by momentum. At low velocities, it is better to use smoke instead of oil due to its control capability and having required shine. It should be considered, it is harder to produce smoke particles in comparison to generate oil particles thanks to required heat. Some other significant point is that, the outlet smoke is hot and has a higher temperature than exterior space which can cause shearing stress in fluid flow. In low velocities, such phenomenon will cause the increase of turbulence because of low momentum.
Keywords: PIV; investment particles; visible field current; smoke generation systems; bubble generation systems.