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You searched for +publisher:"University of New South Wales" +contributor:("Leslie, Greg, Chemical Engineering, Faculty of Engineering, UNSW"). Showing records 1 – 2 of 2 total matches.

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University of New South Wales

1. Tng, Keng Han. Mechanical failures in potable reuse plants: component and system reliability considerations.

Degree: Chemical Engineering, 2018, University of New South Wales

The aim of this thesis was to evaluate the reliability of potable reuse applications from a component and system perspective. Mechanical properties of polyethersulfone (PES) and polyvinylidenefluoride (PVDF) membranes are often used as a surrogate for component reliability. Accelerated ageing with sodium hypochlorite (up to 240,000ppmhr) resulted in a 6% decrease in tensile strength (2.44 to 2.30MPa) for PVDF compared to a 11% decrease (2.47 to 2.19MPa) for PES. Changes in mechanical properties may be interpreted as evidence of potential for failure, however, fibre strain measured in-situ was 60% below loads typically used in tensile tests. Strain, measured by microstrain gauges, was inversely proportional to fibre stiffness and increased at higher aeration intensities and modules’ fibre looseness. Lateral strain ranged from a minimum of 1.3x10-6 (fibre base, no aeration, 2% looseness) to a maximum of 1.2x10-4 (top of fibre, 7.35m3/m2hr, 8% looseness). Measured strains were within the elastic region of PES and PVDF fibres indicating failure results from fatigue. PVDF fibres performance in high cycle fatigue analysis (100,000 cycles) was superior to PES fibres which failed between 94,000 and 42,000 cycles. The significance of component failure was investigated by studying epidemiology data from failures in drinking water systems, selected due to a lack of data on potable reuse plant performance. Of 83 confirmed outbreaks between 2002 and 2012 only 16% were attributed to mechanical failure, which usually occurred in conjunction with a suite of other failure events including operational and maintenance practices. The ability of an Advanced Water Treatment Plant (AWTP) to cope with comparable failure events was assessed using stochastic techniques over a 10 year period for a reference plant, built using mechanical maintenance data from 7 full-scale AWTPs (64 years cumulative operating history). Over a 10 year period, mechanical failure resulting in compromised capacity (downtime) was significantly more frequent than events compromising quality (7.6 vs 2.1 events per year). The frequency of capacity failure events could be reduced through improved maintenance and increased storage capacity compared to increasing critical component redundancy (67% versus 2% reduction in events/year). Consequently, component reliability, while important, is less effective than procedures that enhance system reliability. Advisors/Committee Members: Leslie, Greg, Chemical Engineering, Faculty of Engineering, UNSW, Wang, Yuan, Chemical Engineering, Faculty of Engineering, UNSW.

Subjects/Keywords: Finite Element Analysis; Hollow fibre membranes; Mechanical reliability; Monte Carlo Simulation

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6th Edition):

Tng, K. H. (2018). Mechanical failures in potable reuse plants: component and system reliability considerations. (Doctoral Dissertation). University of New South Wales. Retrieved from http://handle.unsw.edu.au/1959.4/60077 ; https://unsworks.unsw.edu.au/fapi/datastream/unsworks:51180/SOURCE02?view=true

Chicago Manual of Style (16th Edition):

Tng, Keng Han. “Mechanical failures in potable reuse plants: component and system reliability considerations.” 2018. Doctoral Dissertation, University of New South Wales. Accessed December 08, 2019. http://handle.unsw.edu.au/1959.4/60077 ; https://unsworks.unsw.edu.au/fapi/datastream/unsworks:51180/SOURCE02?view=true.

MLA Handbook (7th Edition):

Tng, Keng Han. “Mechanical failures in potable reuse plants: component and system reliability considerations.” 2018. Web. 08 Dec 2019.

Vancouver:

Tng KH. Mechanical failures in potable reuse plants: component and system reliability considerations. [Internet] [Doctoral dissertation]. University of New South Wales; 2018. [cited 2019 Dec 08]. Available from: http://handle.unsw.edu.au/1959.4/60077 ; https://unsworks.unsw.edu.au/fapi/datastream/unsworks:51180/SOURCE02?view=true.

Council of Science Editors:

Tng KH. Mechanical failures in potable reuse plants: component and system reliability considerations. [Doctoral Dissertation]. University of New South Wales; 2018. Available from: http://handle.unsw.edu.au/1959.4/60077 ; https://unsworks.unsw.edu.au/fapi/datastream/unsworks:51180/SOURCE02?view=true


University of New South Wales

2. Radaei, Elham. Investigation of the hydrodynamic behaviour on submerged hollow fibre membrane bioreactors induced by pulse bubble aeration.

Degree: Chemical Engineering, 2019, University of New South Wales

Numerical simulations and empirical observations were used to study pulse aeration in submerged membrane bioreactors (MBRs) of variable fibre packing densities in both Newtonian and Non-Newtonian fluids. Liquid rheology significantly affected simulated bubble behaviour and shear stress distribution. For fibres in direct contact with bubbles, shear stress was 33% higher (1.66 c.f. 1.24 Pa) in non-Newtonian compared to Newtonian fluids, however, for fibres approximately one bubble diameter apart, shear was 72% lower (0.18 c.f. 0.62 Pa) in non-Newtonian compared to Newtonian fluids. Consequently, non-Newtonian properties were used in simulations and experiments to assess variations in bubble volume (58 to 300 ml) and bubble frequency (0.2 to 1.0 Hz). Bubble volume increased effective pulse bubble span of influence. Increasing bubble volume (115 to 300ml) increased shear by 39% on fibres in direct contact and 82% for fibres three bubble diameters away from bubble centre. In contrast, increasing frequency (0.2 to 0.5 Hz) only increased shear by 45% on fibre in direct contact, which was comparable to fibres three bubble diameters away from the bubble centre (42%). Simulations in low packing systems indicated the presence of high and low shear stress peak regions. Fibre fouling in high peak regions decreased by 26% (0.50 to 0.37 kPa/min) as the shear stress increased by 93% (1.40 to 2.71 Pa). However, in low peak regions, fouling decreased by 67% (6 to 2 kPa/min) as the shear increased 12 times (0.04 to 0.50 Pa). Simulated shear stress for 300 ml bubbles at 0.25 and 0.50 Hz in modules with packing density varying from 0.5 to 10.0% of a commercial module decreased by 44% (0.77 to 0.43 Pa for 0.25 Hz) and 39% (1.04 to 0.64 Pa for 0.50 Hz). Bubbles interactions from multiple nozzles were simulated by generating 300 ml bubbles from three nozzles at frequency of 0.5 Hz under synchronous and asynchronous bubble release (1 second delay). For asynchronous conditions, the effective span of influence was 25% wider (20 c.f. 15 cm) compared to synchronous conditions. Simulated shear at 10% (38 m2/m3) density was comparable to literature values for commercial 265 m2/m3 modules. Advisors/Committee Members: Trujillo, Francisco, Chemical Engineering, Faculty of Engineering, UNSW, Leslie, Greg, Chemical Engineering, Faculty of Engineering, UNSW.

Subjects/Keywords: Computational fluid dynamics; Pulse aeration; Submerged hollow fibre membrane bioreactors; Shear stress

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6th Edition):

Radaei, E. (2019). Investigation of the hydrodynamic behaviour on submerged hollow fibre membrane bioreactors induced by pulse bubble aeration. (Doctoral Dissertation). University of New South Wales. Retrieved from http://handle.unsw.edu.au/1959.4/61429 ; https://unsworks.unsw.edu.au/fapi/datastream/unsworks:55458/SOURCE02?view=true

Chicago Manual of Style (16th Edition):

Radaei, Elham. “Investigation of the hydrodynamic behaviour on submerged hollow fibre membrane bioreactors induced by pulse bubble aeration.” 2019. Doctoral Dissertation, University of New South Wales. Accessed December 08, 2019. http://handle.unsw.edu.au/1959.4/61429 ; https://unsworks.unsw.edu.au/fapi/datastream/unsworks:55458/SOURCE02?view=true.

MLA Handbook (7th Edition):

Radaei, Elham. “Investigation of the hydrodynamic behaviour on submerged hollow fibre membrane bioreactors induced by pulse bubble aeration.” 2019. Web. 08 Dec 2019.

Vancouver:

Radaei E. Investigation of the hydrodynamic behaviour on submerged hollow fibre membrane bioreactors induced by pulse bubble aeration. [Internet] [Doctoral dissertation]. University of New South Wales; 2019. [cited 2019 Dec 08]. Available from: http://handle.unsw.edu.au/1959.4/61429 ; https://unsworks.unsw.edu.au/fapi/datastream/unsworks:55458/SOURCE02?view=true.

Council of Science Editors:

Radaei E. Investigation of the hydrodynamic behaviour on submerged hollow fibre membrane bioreactors induced by pulse bubble aeration. [Doctoral Dissertation]. University of New South Wales; 2019. Available from: http://handle.unsw.edu.au/1959.4/61429 ; https://unsworks.unsw.edu.au/fapi/datastream/unsworks:55458/SOURCE02?view=true

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