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A Parametric Study to Quantify the Pressure Drop of Pulsating Flow through Blockages

Pappu, Suryanarayana

Abstract Details

2014, MS, University of Cincinnati, Engineering and Applied Science: Mechanical Engineering.
The current set up is an improvement of a previous set up designed and fabricated to study pulsating flow through blockages[1]. The ultimate objective of such an experiment is to non-invasively be able to detect blockages in a pipe line with such theory and results then extended to detecting blockages in arteries. This facility additionally has the capability of pulsing both upstream as well as downstream of the flow, that is, in the direction as well as the opposite to the direction of the flow to be able to study the effect of pulsing flow better and reach the ultimate goal of a near perfect facility in the future with improvements. The facility has been designed such that pressure measurements can be made at different axial locations along the pipeline. Parameters such as pressure head, frequency of pulsation blockage size and location of pulsation are varied to study the various cases. In addition to this, the duty cycle of the pulse can be changed depending on the systole and diastole ratios. Different wheels have been designed to change the pattern of pulsing for a set specific frequency. The results are looked at in the light of these parameter changes. The fast fourier transforms and pressure time traces are studied. The FFTs show typical fundamental tones at the pulsing frequencies with subsequent harmonics and a gradual roll off after about 20-30Hz. The pressure time traces give us a picture of the pressure cycle during the systole and diastole periods and the fluctuation during those periods. From these basic plots the fundamental pressures are obtained and pressure drops and percentage pressure drops across various blockages and for various pressure heads. As a general observation, the pressure drops are higher with higher pressure heads and greater extent of blockage. With a higher frequency of pulsation the percentage pressure drop reduces and with a more accurate systole diastole ratio the percentage drop is even lower. Upstream pulsing shows a pressure drop and downstream pulsing a pressure rise. A study of the flow rates is also done and it is seen that the pressure drops and flow rates change proportionally for the different blockage cases. The design of the new wheels based on Systole/Diastole ratios from literature allowed for the simulation of a more accurate duty cycle and a pressure curve that matches the aortic curve more accurately. Finally flow visualization is also carried out to study the flow. Vortices are seen downstream of the blockage. In the 96% case there is instant mixing once the dye reaches the downstream side. Finally a conclusion is drawn and some suggestions for future work have been given
Ephraim Gutmark, Ph.D. D.Sc. (Committee Chair)
Urmila Ghia, Ph.D. (Committee Member)
Milind Jog, Ph.D. (Committee Member)
Jeffrey Kastner, Ph.D. (Committee Member)
124 p.

Recommended Citations

Citations

  • Pappu, S. (2014). A Parametric Study to Quantify the Pressure Drop of Pulsating Flow through Blockages [Master's thesis, University of Cincinnati]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1406881302

    APA Style (7th edition)

  • Pappu, Suryanarayana. A Parametric Study to Quantify the Pressure Drop of Pulsating Flow through Blockages. 2014. University of Cincinnati, Master's thesis. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=ucin1406881302.

    MLA Style (8th edition)

  • Pappu, Suryanarayana. "A Parametric Study to Quantify the Pressure Drop of Pulsating Flow through Blockages." Master's thesis, University of Cincinnati, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1406881302

    Chicago Manual of Style (17th edition)