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Papers by Charles Koch

International Journal of Vehicle Design, Mar 20, 2015

... Priyanka Singh received her BASc in Mechanical Engineering from the University of Toronto, Ca... more ... Priyanka Singh received her BASc in Mechanical Engineering from the University of Toronto, Canada, in 2009. ... cyl out, , d d d 0 ivi i vii i i ipii mc T c T m PV mc T + + + = (5) cyl i iii PV mRT = (6) d d BB i i C m m θ ω = − (7) total . i V V = ∑ (8) ...

Journal of Colloid and Interface Science, Feb 15, 2008

Deformation of a fluid drop, suspended in a second immiscible fluid, under the influence of an im... more Deformation of a fluid drop, suspended in a second immiscible fluid, under the influence of an imposed electric field is a widely studied phenomenon. In this paper, the system is analyzed numerically to assess its dynamic behavior. The response of the system to a step change in the electric field is simulated for both perfect and leaky dielectric systems, exploring the influence of the fluid, interfacial, and electrical properties on the system dynamics. For the leaky dielectric case, the dynamic build up of the free charge at the interface, including the effects of convection along the interface due to electrohydrodynamic circulation, is investigated. The departure of the system from linear perturbation theory is explained using these dynamic simulations. The present simulations are compared with analytic solutions, as well as available experimental results, indicating that the predictions from the model are reliable even at considerably large deformations.

Misfire and partial-burn criteria are defined using crank angle based engine parameters and inves... more Misfire and partial-burn criteria are defined using crank angle based engine parameters and investigated on an experimental Homogeneous charge compression ignition (HCCI) single-cylinder engine at 59 operating conditions. The best criteria to distinguish between normal, partial burn and misfire operating conditions for this engine are: the standard deviation of CA10 (Crank angle at which 10 percent of fuel mass has burned) and burn duration. The partial burn limit for five different blends of isooctane and n-heptane fuels is presented. Increasing the manifold pressure at each specific fuel octane number results in a lower equivalence ratio partial burn limit for the engine operating points tested.

SAE Technical Paper Series, 2015

2013 International Conference on Unmanned Aircraft Systems (ICUAS), 2013

ABSTRACT A Hardware-In-The-Loop (HIL) testbed design for small unmanned helicopters is described.... more ABSTRACT A Hardware-In-The-Loop (HIL) testbed design for small unmanned helicopters is described. The testbed provides a safe and low-cost platform to implement control algorithms and tune the control gains in a controlled environment. Specifically, it allows for testing the robustness of the controller to external disturbances by emulating the hover condition. A 6-DOF nonlinear mathematical model of the helicopter has been validated in real flight tests. This model is implemented in real-time to estimates the states of the helicopter which are then used to determine the actual control signals on the testbed. A damping system with a negligible parasitic effect on the dynamics of the helicopter around hover is incorporated into the testbed design to minimize the structural stress on the fuselage in the case of controller failure or a subsystem malfunction. Three experiments including the longitudinal, lateral and heading control tests are performed. Experimental results show that the HIL testbed allows for designing a controller which is robust to the external disturbances, and achieves an accuracy of ±2cm in the position control along the longitudinal and lateral axes in hover, and that of ±1deg around the yaw axis on the heading trajectory tracking.

Application of alternative fuels in high-efficiency combustion modes offers the potential to redu... more Application of alternative fuels in high-efficiency combustion modes offers the potential to reduce demand for petroleum resources. Combustion of Butanol as a promising alternative for both diesel/gasoline fuels is studied in Homogeneous Charge Compression Ignition (HCCI). Combustion characteristics, efficiency, and emissions of Butanol blends in a single cylinder experimental engine are analyzed at over 50 lean-boosted steady-state operating points. The engine is run with several blends of Butanol and n-Heptane at different octane values at a range of equivalence ratios. The engine load range is measured and changes of HCCI heat release and ignition timing to variation of Butanol volume percent are investigated.

International Journal of Vehicle Design

Separation Science and Technology, 2015

ABSTRACT Centrifugal separators have many applications in the separation industry. Comprehensive ... more ABSTRACT Centrifugal separators have many applications in the separation industry. Comprehensive information based on performance and energy consumption for a detailed comparison between different types of centrifugal separators is essential to allow design optimization and is the focus of this work. A framework for comparing performance with an updated performance chart for four types of centrifugal separators and a comparison with a continuous gravity settling tank is described. A model and chart for performance and energy consumption, which makes it possible to compare different separators, is a key result of this work which extends current available handbooks and guidelines.

2005 International Conference on MEMS,NANO and Smart Systems, 2005

ABSTRACT

Proceedings. 2004 International Conference on MEMS, NANO and Smart Systems, 2004. ICMENS 2004., 2004

ASME 2011 Dynamic Systems and Control Conference and Bath/ASME Symposium on Fluid Power and Motion Control, Volume 2, 2011

ASME 2009 Internal Combustion Engine Division Spring Technical Conference, 2009

... Mahdi Shahbakhti Charles Robert Koch∗ Department of Mechanical Engineering University of Albe... more ... Mahdi Shahbakhti Charles Robert Koch∗ Department of Mechanical Engineering University of Alberta Edmonton, Alberta T6G 2G8, Canada Email: bob.koch@ualberta.ca ... Journal of Engineering for Gas Turbines and Power, 130 . [23] Bengtsson, J., 2004. ...

ASME 2011 Internal Combustion Engine Division Fall Technical Conference, 2011

ABSTRACT The novel application of the Discrete Wavelet Transform (DWT) in a real time controller ... more ABSTRACT The novel application of the Discrete Wavelet Transform (DWT) in a real time controller is used to detect and subsequently control knock in a Homogeneous Charge Compression Ignition (HCCI) engine. Classical Fourier techniques for knock detection are discussed and compared to Wavelet Transforms. The Discrete Wavelet Transform filter bank is chosen as the best method for knock detection due to its good time-resolution and low computational requirements. The DWT method is compared with the root mean squared value of the pressure trace as the benchmark method for determining knock and the two methods are linearly correlated. Using the DWT method for knock detection and modulating fuel octane, both a Proportional Integral (PI) and PI with Feed-forward control are implemented. Both of these methods reduce knock intensity for a step increase in engine load. The combination of Feed-forward with PI feedback is found to be slightly more effective than just PI feedback control.

2006 American Control Conference, 2006

A promising method for enhancing automotive internal combustion engine efficiency uses solenoid a... more A promising method for enhancing automotive internal combustion engine efficiency uses solenoid actuators to directly control gas exchange valves. Mitigation of valve seating velocities is challenging due to phenomena such as magnetic saturation and pressure disturbances. Production implementation of an electromagnetic valvetrain will require the development of cost effective yet accurate sensors for robust feedback control. A method of magnetic

Physics of Fluids A: Fluid Dynamics, 1989

Volume 7A: Fluids Engineering Systems and Technologies, 2013

ABSTRACT Rapid characterization of complex liquids such as solutions, mixtures, dispersions, and ... more ABSTRACT Rapid characterization of complex liquids such as solutions, mixtures, dispersions, and emulsions is useful in a variety of industrial applications ranging from cosmetics, pharmaceuticals, to petroleum production. An electrical impedance spectroscopy (EIS) based technique for rapidly determining the characteristics of liquid-liquid mixtures is presented in this study. A milli-fluidic liquid film impedance measurement cell is developed employing 3D printing technology. The cell is tested using glycerol-water mixtures followed by castor oil in water emulsion samples. Frequency response analysis and equivalent circuit modeling are performed on each sample to quantify the emulsion properties in the form of equivalent capacitance and resistance. The developed technique provides an inexpensive and disposable, yet robust experimental platform for applying EIS to investigation and rapid estimation of different properties of oil-water emulsions.

Langmuir : the ACS journal of surfaces and colloids, Jan 16, 2014

The effect of electrostatic force on the dynamics, morphological evolution, and drainage time of ... more The effect of electrostatic force on the dynamics, morphological evolution, and drainage time of ultrathin liquid bilayers (<100 nm) are investigated for perfect dielectric-perfect dielectric (PD-PD) and ionic liquid-perfect dielectric (IL-PD) bilayers. The weakly nonlinear "thin film" equation is solved numerically to obtain spatiotemporal evolution of the liquid-liquid interface responses to transverse electric field. In order to predict the electrostatic component of conjoining/disjoining pressure acting on the interface for IL-PD bilayers, an analytical model is developed using the nonlinear Poisson-Boltzmann equation. It is found that IL-PD bilayers with electric permittivity ratio of layers (lower to top), εr, greater than one remain stable under an applied electric field. An extensive numerical study is carried out to generate a map based on εr and the initial mean thickness of the lower layer. This map is used to predict the formation of various structures on PD...

Journal of Fluids Engineering, 2014