QSpace Collection:
http://hdl.handle.net/1974/802
2015-07-08T02:20:49Z
2015-07-08T02:20:49Z
Standard and Multi-Material Topology Optimization Design for Automotive Structures
Li, CHAO
http://hdl.handle.net/1974/13155
2015-06-28T05:18:27Z
2015-06-26T04:00:00Z
Title: Standard and Multi-Material Topology Optimization Design for Automotive Structures
Authors: Li, CHAO
Abstract: Abstract
Lightweight design, drawing an increasing attention for structural design in automotive industry, is recognized as an efficient and immediate way to improve fuel efficiency and reduce CO2 emissions. Topology optimization, by determining an optimum geometry and material distribution of a structure at an early design stage, serves as the cornerstone for not only increasing the performance of products but also streamlining the entire structural design process.
In this thesis, the theory, algorithm, implementation and application of both of the traditional single-material topology optimization and an advanced multi-material topology optimization are presented, which can solve real-world engineering problems in the automotive industry. This research will advance structural optimization methods in academic research, and it is also expected that the developed method and tool would make a profound impact in the design of automotive parts and assemblies in the field.
In Chapter 2 and Chapter 3, the traditional single-material topology optimization is explained, and it is applied to the design of an automotive engine cradle and a cross-car-beam (CCB). The computational method helped an automotive tier-1 supplier company produce better engineering products while reducing time and cost of the design process.
In Chapter 4, a multi-material topology optimization methodology and its numerical tool are presented. This innovative approach can effectively deal with multiple, dissimilar materials in structural design. Advanced mathematical algorithms, numerical implementation, and practical applications are discussed in detail, and effectiveness and efficiency of the methodology is demonstrated with a variety of engineering problems.
Detailed discussions are included in Chapter 5, and recommendations for future work are discussed in Chapter 6.
Description: Thesis (Ph.D, Mechanical and Materials Engineering) -- Queen's University, 2015-06-25 23:01:03.673
2015-06-26T04:00:00Z
Convective Heat Transfer from a Recessed Window Covered By a Top Down – Bottom Up Single-Layer Honeycomb Blind
Mansouri Birjandi, Neda
http://hdl.handle.net/1974/13139
2015-06-22T22:24:16Z
2015-06-22T04:00:00Z
Title: Convective Heat Transfer from a Recessed Window Covered By a Top Down – Bottom Up Single-Layer Honeycomb Blind
Authors: Mansouri Birjandi, Neda
Abstract: Honeycomb (or cellular) Top Down–Bottom Up blinds are quite widely available. When this type of blind is closed there are two or more vertical blind portions and a series of horizontal or near-horizontal blind portions joining the vertical portions forming a series of cells. When such a blind is open the vertical portions of the blind bend decreasing the blind height.
A honeycomb blind with a single column of cells in two different shapes was considered in the present study. Results have also been obtained for a Top Down-Bottom Up plane blind for comparative purposes. The effect of the dimensionless top and bottom blind openings, shape of the blind and dimensionless window recess depth on the convective heat transfer from a window to the surrounding room was numerically investigated. The case where the window is at a higher temperature than room was considered. Laminar and turbulent flow can occur over the window system for the conditions considered in this work.
The numerical results were obtained using the commercial CFD finite-volume based solver FLUENT© and using the standard k-epsilon turbulence model. Some experimental tests were undertaken for a window-blind system with plane blind to validate the numerical results obtained in this work.
From the results of this study it is concluded that when the blind is fully closed the mean window heat transfer rate for a case where a honeycomb blind is used is less than that for the case where a plane blind is used. However when the blind is partially open, the heat transfer rate from a window-blind system with a honeycomb blind is higher than it is for the case where a plane blind is used at high Rayleigh numbers considered. When the blind is partially open, increasing the dimensionless top blind opening or decreasing the dimensionless bottom blind opening increases the mean window Nusselt number at the higher Rayleigh numbers considered. The results indicate that the effect of the dimensionless window recess depth on the mean window Nusselt number is different in each flow regime i.e. with laminar, transitional and turbulent flow.
Description: Thesis (Master, Mechanical and Materials Engineering) -- Queen's University, 2015-06-22 16:33:26.251
2015-06-22T04:00:00Z
Evaluation of Energy Systems for Distributed Green Data Centres using Lifetime Cash Flow Analysis
Werden, PAUL
http://hdl.handle.net/1974/13133
2015-06-23T05:13:32Z
2015-06-16T04:00:00Z
Title: Evaluation of Energy Systems for Distributed Green Data Centres using Lifetime Cash Flow Analysis
Authors: Werden, PAUL
Abstract: Distributed Green Data Centres (DGDC) are micro-data centre collocated with renewable energy generation sources. Multiple DGDCs are networked together to share information and computing processes. In this thesis, a year-long DGDC simulation balances the computing demand and supply each hour with variable renewable energy production and electricity prices. A five-year Net Present Value (NPV) analysis determines the optimal energy system with the lowest lifetime cost of computing (LCC), equal to the net present value divided by the amount of electricity used for computing. The LCC fairly compares alternative energy systems by the ability to provide lowest cost computing.
Grid-isolated DGDCs with 100kW of solar panels have an optimal computing capacity of 20kW and a 20 hour battery capacity. When the optimal grid-isolated DGDC is connected to the Ithaca electricity grid the battery storage is 10 hours and the LCC is $10/MWh less. The NYSERDA Solar PV Program applied to a grid-tied DGDC reduces the panel cost by $76,806 and reduces the LCC by 8.5%. Grid-tied DGDCs in Ontario are not feasible due to the high Feed-in-Tariff incentive to sell electricity.
A grid-isolated DGDC is optimal in Ithaca when the cost of transmission infrastructure upgrades are greater than $8291 or when the value of a generated Renewable Energy Credits (REC) are higher than $38/MWh. Both on- and off-grid DGDCs use equal amount of energy for computing but a grid-tied DGDC is able to sell 26% of electricity from a 100kW solar system with only 10kW of transmission capacity.
Grid-tied DGDCs are active market participants responding to electricity price signals. DGDCs buy low-cost electricity and sell electricity when prices are high. On average the cost of energy used by the DGDC is $19/MWh less than grid electricity. DGDCs provide a reliable source of computing for high-priority applications such as video streaming as well as a low-cost option for time independent tasks such as batch processes or cloud storage.
Description: Thesis (Master, Mechanical and Materials Engineering) -- Queen's University, 2015-06-16 18:42:14.335
2015-06-16T04:00:00Z
Photovoltaic system performance enhancement: Validated modeling methodologies for the improvement of PV system design
Andrews, ROBERT
http://hdl.handle.net/1974/13112
2015-06-03T16:59:17Z
2015-06-03T04:00:00Z
Title: Photovoltaic system performance enhancement: Validated modeling methodologies for the improvement of PV system design
Authors: Andrews, ROBERT
Abstract: Photovoltaic (PV) energy generation is rapidly expanding, driven by decreases in capital and operational costs. Modeling of expected energy output is a major factor affecting the operation and construction of these systems, and the objective of this thesis is to present methodologies and tools which improve PV system modeling. Initially, the modeling of short circuit current in PV modules is investigated and demonstrates techniques for filtering of data from fielded PV modules, allowing performance metrics traditionally derived in laboratory tests to be derived from data collected from stationary outdoors systems.
The spectral component of irradiance is important for PV system modeling, and dataset of hourly spectral irradiance from 250nm-2500nm was collected from November 2012 to April 2014. This data set can be used to validate the derived equations from the previous chapter, and is aimed to enable improved modeling of spectra using an iterative methodology.
Albedo, or reflected, irradiance is then considered, where effects of spectral mismatch can be substantial. It was found that spectral mismatch error can lead to modeling errors ranging from 0.04 % to 10.5 % as PV module tilt increases from 25 degrees to 90 degrees from the horizontal, and methods of predicting and modeling this albedo spectral mismatch were presented.
Detailed methods for identifying snowfall losses were investigated, and provided results from two typical winters in 2010 and 2011. It was found that there is not a simple correlation between meteorological factors and snowfall losses, which warrant further investigation in the the modeling an prediction of this phenomenon. Consequently, an empirical lag 1 time-series model is proposed, based on the stochastic variation in snow depth that is able to predict daily snow fall losses within 3%.
Finally, an investigation is undertaken into the use of planar diffuse reflectors for albedo augmentation. It was found experimentally that such a system can increase system output by 18%. A physically based non-empirical model was developed that predicted system output with a bias error of 1%, and was used to perform a sensitivity analysis that demonstrated a yearly energy increase of 30% is achievable at the latitude of Kingston, Ontario.
Description: Thesis (Ph.D, Mechanical and Materials Engineering) -- Queen's University, 2015-06-02 19:48:18.104
2015-06-03T04:00:00Z