Parameterization of baffle drop shafts for hydropower conveyance systems : a physical model-based study | |
| Author | Samudio, Larriz Mondala |
| Call Number | AIT Thesis no.WM-22-04 |
| Subject(s) | Water-power Air Entrainment Water |
| Note | A thesis submitted in partial fulfillment of the requirements for the degree of Master of Engineering in Water Engineering and Management |
| Publisher | Asian Institute of Technology |
| Abstract | Baffle drop shaft has been used in hydropower conveyance systems to dissipate energy and minimize air entrainment. With the limited studies for this structure that mainly focuses on its hydraulic characteristics and energy dissipation, assessment of air entrainment is also required to prevent flow instabilities, turbine efficiency reduction, and failure due to high impact energy, air entrainment, and cavitation. A constructed physical hydraulic model of 1:10 geometric scale was utilized to propose a novel parameterization approach of baffle drop shafts for hydropower conveyance systems in terms of air entrainment and energy dissipation. A proposed integrated approach using isokinetic sampling and digital image processing for the assessment of air entrainment was implemented to address errors from image distortion and overlapping of bubbles. Results from the study show that the design parameters significantly affect the air entrainment with a reduction of 56-68% when shaft diameter is increased from 8m to 9m and increasing discharge from 12.45 to 16.60 m3 /s has the highest increase of 408.16 cm3 /s. On the other hand, it is only discharge that significantly affects the global energy dissipation rate in the baffle drop shaft which ranges from 35.68 to 59.20%. Dimensionless relationships were established between the design parameters and air entrainment and energy dissipation rate using multiple linear regression analysis (MLRA). These developed regression models can be used for the preliminary design of baffle drop shaft to attain its required performance where design guidelines were also proposed. |
| Year | 2022 |
| Type | Thesis |
| School | School of Engineering and Technology (SET) |
| Department | Department of Civil and Infrastucture Engineering (DCIE) |
| Academic Program/FoS | Water Engineering and Management (WM) |
| Chairperson(s) | Ho Huu Loc |
| Examination Committee(s) | Shrestha, Sangam;Shanmugam, Mohana Sundaram;Roa, Arturo Gementiza |
| Scholarship Donor(s) | Asian Development Bank – Japan Scholarship Program (ADB-JSP) |
| Degree | Thesis (M. Eng.) - Asian Institute of Technology, 2022 |