David S-K Ting

University of Windsor · Turbulence and Energy Laboratory

As an emerging flexible-scale energy storage technology, underwater compressed gas energy storage (UW-CGES) is regarded as a promising energy storage option for offshore platforms, offshore renewable energy farms, islands, coastal cities, etc. Liquid accumulation often occurs in underwater gas transmission pipelines, which is a challenge to overcom...

Vertical Axis Wind Turbines (VAWT) are currently viewed as promising renewable energy sources. However, they are still insufficiently investigated and implemented. H-Blade VAWT specifically are considered very advantageous, but they suffer from induced drag generated from the vortical flow at the tips of the airfoil. This paper suggests winglets as...

Irrigation water temperature plays an essential role in yield and quality of greenhouse products. In the summer, the irrigation water can be warming than desirable, leading to certain problems such as root diseases. In this paper, the performance of using stormwater pond to cool irrigation water for a commercial greenhouse was studied using the Tra...

Two-phase bubbly flow can lead to challenges during the charging period for hydraulically-compensated Compressed Air Energy Storage systems. In this study, upward two-phase flow systems have been investigated in large diameter vertical pipes to better understand when the transitions to problematic flow regimes occur. A comprehensive dimensional ana...

Threats to water supply systems have increased in number and intensity. Natural disasters such as earthquakes have caused different types of damage to water distribution networks (WDN), particularly for those with aged infrastructure. This paper investigates the resilience of an existing water distribution network under seismic hazard. An earthquak...

Selection of the best component arrangement and sizing measurement for hybrid energy systems (HES) is vital to provide a reliable, consistent, and cost-effective energy supply. This study investigates a techno-economic feasibility analysis of stand-alone HES on Western side of Pelee Island, Canada, whose load is 2426 kWh/day. Several hybridization...

The shape design for a thermoelectric generator (TEG) plays an important role in its performance. In this paper, a hyperbolic function was introduced to design a variable cross-section TEG module to optimize the configuration for maximum power generation and efficiency was sought. A comprehensive thermodynamic model was applied to establish the gov...

Governments have implemented different interventions and response models to combat the spread of COVID-19. The necessary intensity and frequency of control measures require us to project the number of infected cases. Three short-term forecasting models were proposed to predict the total number of infected cases in Canada for a number of days ahead....

Underwater compressed air energy storage was developed from its terrestrial counterpart. It has also evolved to underwater compressed natural gas and hydrogen energy storage in recent years. UWCGES is a promising energy storage technology for the marine environment and subsequently of recent significant interest attention. However, it is still imma...

A TEG typically operates in a dynamic environment and efforts invested on furthering TEG should focus on the dynamic performance. A hyperbolically-shaped variable cross-section design is proposed to improve a TEG’s performance under a sinusoidal thermal load. To this end, a transient TEG model was established in SIMULINK in which the TEG heat trans...

The use of Phase Change Material (PCM) in the building envelope is a promising technology for providing energy savings. In this study, the effectiveness of incorporation a honeycomb PCM to the walls of a retrofitted building in Ottawa, Canada is investigated in terms of reduction of heat flux through the walls. The climatic condition of Ottawa has...

As a flexible-scale energy storage technology, underwater compressed gas energy storage is an emerging enabler of the transition to renewable and sustainable energy structure. Liquid accumulation often occurs in the process of underwater pipeline gas transmission, posing a challenge that must be overcome. In this study, an experimental investigatio...

Turbulent flow downstream of a pair of 12.7-mm wide (W) and 25.4-mm high rectangular flexible strips was characterized using a 3D hotwire anemometer. The rectangular strips were at a separation distance of 3 W, 2 W, and 1 W and the Reynolds number based on the strip width was fixed at 8500. Discrete wavelet transform was employed to investigate the...

Condition Monitoring (CM) is an essential element of securing reliable operating conditions of Wind Turbines (WT) in a wind farm. CM helps optimize maintenance by providing Remaining Useful Life (RUL) forecast. However, the expected RUL is not often reliable due to uncertainty associated with the prediction horizon. In this paper, we employ high-le...

Hydrogen-based microgrids are receiving attention as critical pathways are being charted for the decarbonization of our thermal, transport, and power grids. In this article, clean, cost-effective, and reliable hybrid microgrid designs are developed to satisfy hydrogen and electricity loads in three energy-stressed islands of Eastern Canada, namely...

Thermofluids: From Nature to Engineering presents the fundamentals of thermofluids in an accessible and student-friendly way. Author David Ting applies his 23 years of teaching to this practical reference which works to clarify phenomena, concepts and processes via nature-inspired examples, giving the readers a well-rounded understanding of the top...

This chapter commences by differentiating forced convection from the natural convection. The convection heat transfer coefficient is then elucidated. The familiar forced convection over a flat plate is presented before highlighting the key parameters underlying forced convection. The fundamental factors are grouped into nondimensional Nusselt numbe...

We learn to appreciate the radiating Sun in this chapter. The ideal black body radiation is cast as the reference for everyday gray body radiation. The utilization of the radiation heat transfer equation for calculating radiation heat transfer is illustrated. Absorptivity, transmissivity, and reflectivity are explained by invoking the conservation...

This chapter is about the internal flow of Newtonian fluids. It prescribes laminar, transition, and turbulent pipe flows in terms of Reynolds number. It explains that a finite entrance region is required for the flow to develop into a fully developed pipe flow. The pressure drop-wall shear relation is then delineated. Also expounded is the energy c...

This chapter discusses energy in its various forms in the context of the first law of thermodynamics. It delineates open, closed, and isolated thermodynamic systems. The difference between work transfer and heat transfer is elucidated. The path-dependent moving-boundary work is illustrated. After introducing enthalpy its relation with internal ener...

This chapter first acquaints the readers with the three laws of thermodynamics. Then, it communicates energy has both quantity and quality, and energy naturally flows in the decreasing-quality direction. Entropy can be perceived in terms of disorder, and it is generated in all real processes. The concept of thermal reservoirs as the heat source and...

This chapter begins by enlightening the readers on how animals thrive by exploiting intelligently designed heat exchangers. It then differentiates indirect or noncontact heat exchanger from direct contact heat exchangers. Indirect heat exchangers, the focus of this chapter, are categorized based on flow configuration into counter-flow, parallel flo...

This chapter defines and differentiates streamline, streakline, and pathline. Newton's second law is applied to analyze fluid flow. For steady, incompressible, and frictionless fluid flow along a streamline, the Bernoulli equation is derived. The concepts and applications of static, stagnation, dynamic, and total pressures are delineated. Lastly, e...

This chapter introduces the concept of a lumped system, which is well suited for transient heat conduction analysis when the conditions are appropriate. The Biot number, which denotes the ratio of internal conductance resistance within the body over the external convective resistance at the surface of the body, is delineated. The smaller the Biot n...

This chapter conveys the importance of dimensions and dimension homogeneity. It illustrates the usefulness of the dimensional analysis. The established Buckingham Pi theorem is expounded and its utilization is demonstrated via practical examples. Lastly, the eminent dimensionless parameters in fluid mechanics are recognized and explained.

Ecology is introduced in this chapter. The importance of ecology in engineering is illustrated. The focus is on thermoregulation. There is much room for further engineering by mimicking how endotherms and ectotherms regulate their body temperature. The parallel between the four classical laws of ecology and the first and second laws of thermodynami...

This chapter explains what thermodynamics is. It illustrates the conservation of energy using everyday examples, clearly revealing the transformation of energy from one form to another. The quality of energy is demonstrated alongside with the transformation of energy, that is, energy naturally transforms progressively to lower quality form. Also de...

This chapter explains what thermal energy is. The meaning of specific heat is expounded with the help of practical everyday examples. It then differentiates thermal energy in transient, heat transfer, from thermodynamics. The chapter concludes with the three fundamental heat transfer mechanisms, conduction, convection, and radiation.

This chapter differentiates a fluid from a solid. It explains what a continuum fluid is. Examples of beautiful natural fluids in motions are used to illustrate the importance of moving fluids. Fluid viscosity is timely introduced, where viscosity is not a function of flow shear for Newtonian fluids. The chapter wraps up by providing a general categ...

The readers are first made aware of everyday external flows in this chapter. Lift and drag are then introduced, followed by discussion on fluid viscosity and boundary layer. Flow over a flat plate is subsequently presented. The boundary layer development from laminar to transition to turbulent is delineated. Bluff body aerodynamics, including vorte...

This chapter introduces the subject, thermofluids. Thermofluids encompasses thermodynamics, fluid mechanics, and heat transfer. Thermodynamics is the study of energy. Fluid mechanics is the study of energy and forces in a fluid. Heat transfer is the study of transfer of thermal energy. The three fundamental heat transfer mechanisms are conduction,...

The chapter starts with an introduction of natural convection and thermals. It explicates the underlying mechanism of natural convection. The relevant parameters are combined into nondimensional groups. The classical Rayleigh–Bernard convection is conveyed before describing natural convection inside a cavity in practice. Natural convection along a...

This chapter is about steady heat conduction. It commences by explaining Fourier's law of heat conduction. This leads to the inverse relationship between thermal conductivity and temperature gradient. The analogy between electric current flow and heat flow is then drawn. This is followed by the similitude between electric resistance and thermal res...

This chapter is about the pressure distribution in a fluid at rest. The working principles of manometers and barometers are disclosed. It also details the calculations of the hydrostatic pressure force on a surface submerged in a static fluid. The Archimedes’ principle is invoked to demonstrate the underlying physics of buoyancy. Lastly, the stabil...

Low energy efficiency is one of the most significant shortcomings of industrial pneumatic systems. The isobaric air storage tank is a new concept for improving the energy efficiency of pneumatic systems. In this study, comprehensive accumulated and transient exergy analyses are conducted to provide insight into the energy‐saving mechanism of isobar...

Flexible pressure sensors with self-healing abilities for wearable electronics are being developed, but generally either lack autonomous self-healing properties or require sophisticated material processing methods. To address this challenge, we developed flexible, low-cost and autonomously self-healing capacitive sensors using a crosslinked poly(di...

Wind power is a pillar of low emission energy systems. Designing more efficient wind turbines and farms, and increasing reliability and flexibility, is an area of intense research and development. In order to overcome the intermittent character of wind power, both the individual turbines and the wind farm as a whole must be considered. Many recent...

This paper presents a T-junction microdroplet generator equipped with a pneumatic actuation for controlling the droplet size. The multi-layer device is compatible with rapid manufacturing using a desktop-based laser cutter to fabricate the fluidic and pneumatic layers. A T-junction fluidic layer sits at the bottom and the control layer consists of...

Underwater energy storage provides an alternative to conventional underground, tank, and floating storage. This study presents an underwater energy storage accumulator concept and investigates the hydrodynamic characteristics of a full-scale 1000 m3 accumulator under different flow conditions. Numerical simulations are carried out using an LES turb...

Efficiency and cost-effectiveness play dominant roles in the commercialization of thermoelectric generator (TEG) technology. In this paper, the exergy analysis of a TEG module with 199 TE couples was considered. Two objective functions, the exergy efficiency and levelized cost of energy (LCOE), were established for exergoeconomic analysis. The geom...

Compared with traditional isochoric storage of compressed air in pneumatic systems, isobaric storage possesses many advantages. In this study, a novel isobaric compressed air storage device is proposed by introducing compressed gas energy storage and a nonlinear cam transformation mechanism. The critical profiles on both sides of cam are deduced an...

The prevailing atmospheric wind can be manipulated to enhance the convective cooling of a solar photovoltaic panel and thus its energy conversion efficiency. The transverse spacing of a delta winglet pair was examined for its role in convective heat transfer enhancement. A pair of winglets with an inclination angle of 90° and a chord/height ratio o...

The turbulent strain rate generated by a pair of 25.4 mm tall and 12.7 mm wide (W) rectangular strips at a Reynolds number based on the strip width of 8500 was measured using a 3D hotwire probe in a wind tunnel. The strips were placed side-by-side separated by 3W, 2W, and 1W. The convective heat transfer enhancement, denoted by the normalized Nusse...

There is growing interest in multi-purpose offshore floating platforms that: harvest energy from the sun, wind, water, and waves; desalinize water; host agriculture and aquaculture; and house residents. While there are some basic commonalities with well established, oil and gas platforms, lighter variants are functionally different with little wind...

This paper presents a novel MEMS based ring resonator design inspired by the rose petal structure. The proposed design has four petal springs supporting the ring structure surrounded by sense electrodes, with a stem in the middle offering simplicity in fabrication and easy control of movement in the driving and sensing modes. An equation was develo...

Employing turbulence generators, such as rectangular flexible strips, is a simple and effective approach to enhancing forced convection. In the current study, 12.7 mm wide rectangular flexible strips (with thickness of 0.1 mm, 0.2 mm and 0.25 mm, height of 25.4 mm, 38.1 mm and 50.8 mm, transversal spacing of 12.7 mm, 25.4 mm and 38.1 mm) were inves...

Delta winglets are an effective means for enhancing heat exchange and thus the performance of renewable energy technologies, including solar energy. A pair of 0.1 mm thick, 15 mm high (h) and 30 mm long aluminum winglets separated with transversal spacing, s, of 2h, h and 0 were scrutinized in a closed-loop wind tunnel at a Reynolds number based on...

Equations are essential in engineering, as they are in life. Engineers, at times, have to build a model and perform simulations to study the real system of interest. One way to categorize models is to divide them into the following two kinds: descriptive model and predictive model. More specifically, we can classify models into four main types: ana...

Effective exchange of thermal energy is present in literally all creatures. Heat exchange can take place without direct contact. A heat exchanger that operates without the warm and cold streams mixing or contacting each other is called an indirect contact heat exchanger, or simply indirect heat exchanger. It is, however, much more effective as far...

Nearly all mechanical, chemical, and environmental engineers routinely tap into knowledge of many thermofluid components. Some of the most common thermofluid systems include power plants and air conditioning systems. The associated major components or devices are combustors, boilers, turbines, condensers, engines, etc. The minor components include...

Engineering economics is the subset of economics that applies economic principles in evaluating engineering decisions. This chapter looks at two age‐old questions, that is, is time money? Is knowledge money? Whether money makes the world go around or not, other than the very frugal few, the rest of us have money flowing in and out of our pockets li...

The Lagrange (or Lagrangian) Multiplier is based on the aforementioned continuous differentiable calculus to deduce the zero slope which corresponds to extrema. As it is a calculus method, the Lagrange Multiplier works only for differentiable functions and equality constraints. Fortunately, very often, curve fitting can be employed to convert discr...

Performance and economic analyses of a hybrid solar thermal/photovoltaic-battery energy storage (ST/PV-BES) system for a commercial greenhouse were developed. One of the objectives of the study is to evaluate the best configuration of photovoltaic (PV) and solar thermal (ST) modules, and battery energy storage size to have the minimum levelized cos...

This chapter discusses the various approaches of optimization. Only basic calculus is needed to solve the formulated problems in all the examples furnished in this chapter. The focus is on illustrating the formulation of the problem at hand. The chapter looks at the formulation and optimization in terms of preventing heat loss of a simple thermoflu...

There are basically three types of optimization approaches. These are: elimination methods, hill‐climbing techniques, and constrained optimization. Under the elimination type, the most common methods are: the Exhaustive Search, the Dichotomous Search, the Fibonacci Search, and the Golden Section Search. This chapter first expounds elimination metho...

Programming simply refers to optimization. The most common types of programming are: geometric programming, linear programming, and dynamic programming. This chapter focuses on geometric programming. Once geometric programming is applied, the optimal solution and the sensitivity of the solution to changes in the constraints can easily be deduced. G...

System simulation is the deduction of operating variables such as pressure, temperature, volume flow rate, and heat transfer rate. The simulation is typically conducted under steady‐state operation of the concerned system, where the equations describing the component performance characteristics, the thermodynamic properties at the operating conditi...

In this study, energy, exergy, and environmental (3E) assessments have been conducted on a proposed combined-cycle power plant (CCPP) with three pressure levels of the HRSG and reheating process. 3-E design approaches cross-link mechano-electric and environmental objectives. Herewith, the suggested combined-cycle is formed by a gas unit, condenser,...

This work deals with the efficiency of cavern-based compressed air energy storage (CAES) facilities. Due to the complex interactions of the components of cavern-based CAES plants, a small deviation from designed for operating conditions can significantly alter the efficiency of the system. In this work, the sensitivity of individual system componen...

A delta winglet (DW) with an aspect ratio (c/h) of 2 and an attack angle of 30 degrees was mounted on a heated flat plate to scrutinize the role of its inclination angle (60°, 90° and 120°) on convection heat transfer enhancement. The experiment was conducted at a Reynolds number, Reh, of 6300 in a wind tunnel. The heat transfer enhancement deduced...

The present investigation deals with the flow behind a torus, placed normal to the flow direction in three different aspect ratios (defined as the main diameter to the cross-sectional diameter of the torus) of 2, 3 and 5 at a constant Reynolds number of 9000. The Large Eddy Simulations (LES) are carried out to model the three-dimensional flow field...

This book includes the proceedings of the Sustaining Tomorrow 2020 symposium and summit which bring together research from experts in academia, industry, and policy arenas to uncover the challenges and to forge solutions to sustain tomorrow. To sustain tomorrow, we need to continuously make headway in Agriculture, Engineering, Energy, Environment,...

A solid-state thermoelectric generator (TEG) can be impelled by heat flow to generate power. The device has been applied in heat recovery, with sources ranging from hot liquids to exhaust gases. In this paper, a TEG module involving 199 pairs of couples (PN junctions) was modeled by ANSYS Workbench. After being validated using experimental results...

Due to the dynamic interactions of the components of cavern‐based compressed air energy storage plants, optimizing this system is challenging and a small change in the design parameters, such mass flow rate, compression ratio, expansion ratio can significantly alter the efficiency of the entire system. An adaptive genetic algorithm has been invoked...

Turbulence generators such as a 25.4 mm tall, 12.7 mm wide (W) and 0.1 mm thick rectangular flexible strip can provide a robust means of enhancing convective heat transfer. This wind-tunnel study aimed at uncovering the effect of freestream turbulence on heat convection enhancement of a flat surface by a flexible strip. The freestream turbulence wa...

With the recent development of thermoelectric materials, thermoelectric generators (TEGs) have become a technology with a huge potential in the energy recovery field. A TEG module consisted of 199 cascade couples was analyzed by a one-dimensional steady-state thermodynamic model. Meanwhile, using the thermodynamic analysis results, two discrete obj...

As wind energy is becoming a significant utility source, minimizing the Operation and Maintenance (O&M) expenses has raised a crucial issue to make wind energy competitive to fossil fuels. Wind Turbines (WTs) are subject to unexpected failures due to operational and environmental conditions, aging, etc. An accurate estimation of time to failures as...

A pair of 12.7 mm wide (W) and 25.4 mm tall rectangular flexible strips made of 0.1 mm thick aluminum sheet was employed to enhance convective heat transfer from a flat surface in a closed-loop wind tunnel. The strip pair was placed side-by-side with a spacing of 1W, 2W and 3W. The incoming wind velocity was fixed at 10 m/s, resulting in a Reynolds...

Gear faults contribute to a significant portion of failures in wind turbine system. As such, condition monitoring and fault detection of these components assist in maintenance scheduling; hence, preventing catastrophic failures of the gearbox. This paper introduces a new hybrid fault detection approach to detect gear faults in wind turbines. to acc...

Regression Tree (RT) forecasting models are widely used in short-term demand forecasting. Likewise, Self-Organizing Maps (SOM) models are known for their ability to cluster and organize unlabeled big data. Herein, a combination of these two Machine Learning (ML) techniques is proposed and compared to a standalone RT and a Seasonal Autoregressive In...

The enhancement of the breakdown power during the spark discharge process has been proved to be beneficial for the flame kernel formation process under lean/diluted conditions. Such a strategy is realized by using a conventional transistor coil ignition system with an add-on capacitance in parallel to the spark plug gap in this paper. In practical...

The failure progression of Wind Turbine (WT) bearings comprises of multiple degraded health states due to applied load by Varying Operating Conditions (VOC). Therefore, determining the VOC impact on the failure dynamics severity is an essential task for bearing failure prognostics. This paper introduces a hybrid prognosis method using real-time Sup...

Environmental Management of Air, Water, Agriculture, and Energy brings together the most current state of knowledge on four major elements for sustaining life on planet Earth: air, water, food, and energy. It examines how green technology aids in mitigating the global water, energy, and climate change crises, including the use of electrostatic forc...

A 0.1 mm thick and 12.7 mm wide (W) rectangular flexible strip is experimentally investigated for its effectiveness in boosting the convective cooling from a heated flat plate in a wind tunnel. Three strip height, 25.4 mm, 38.1 mm and 50.8 mm, were explored at a 10 m/s wind, and a Reynolds number of 8500, based on the strip width. The heat transfer...

Imperfectly round bridge stay cable cross section is speculated to be a key factor for wind-induced large-amplitude cable vibrations observed on site. A delayed detached eddy simulation implemented in Open source Field Operation and Manipulation is used to investigate the flow structure around and in the near-wake of an imperfectly round circular c...