Engineering Center, Room 301
115 Library Drive
Rochester, MI 48309-4479
(map)
Dean's Office: (248) 370-2217
Academic Advising: (248) 370-2201
SECSDean@oakland.edu

Kobus

Christopher J. Kobus, Ph.D.Christopher J. Kobus, Ph.D.
Director of Outreach and Recruitment, 
Associate Professor
Mechanical Engineering Department
301 EC; (248) 370-2489; Fax: (248) 370-4416
cjkobus@oakland.edu
Website

Ph.D., Oakland University, 1998
  • Joined Oakland University in 1998
  • Member of ASME, ASEE, Tau Beta Pi

RESEARCH

  • Transient and Unstable Behavior in Two-Phase Evaporating and Condensing Flow; Single and Multitube Systems
  • Combined Forced and Natural Convective Heat Transfer; Boundary Layer Theory and Experimental Techniques
  • Analytical and Experimental Techniques Associated with Steady-State and Time Varying Fluid and Thermal Systems, Components, Processes and Phenomena
  1. Transient and Unstable Behavior in Two-Phase Evaporating and Condensing Flow; Single and Multitube Systems. Large flow oscillations of the condensate in single-tube and multitube condensing flow systems can substantially affect performance, control and safety. The governing equations features the System Mean Void Fraction (SMVF) Model, a one-dimensional, two-fluid, distributed parameter integral model describing the primary physical mechanisms within the two-phase region and incorporating a non-fluctuating system mean void fraction. This concept makes the problem open to closed-form analytical solution, and yields valuable insight into the relevant physical parameters of the transient characteristics of the condensing flow systems.

    Research in Progress: Prediction of Transients and Instabilities in Multitube Two-Phase Condensing Flow Systems; Influence of Heat Flux on Horizontal Single-Tube Condensing Flow Systems; Influence of Gravity in Vertical Condensing Flow Systems, Upflow and Downflow; Effect of Subcooled Liquid Inertia on Transient- and Frequency Response Characteristics of Single and Multitube Condensing Flow Sytems.
  2. Combined Forced and Natural Convective Heat Transfer; Boundary Layer Theory and Experimental Techniques. In combined, or mixed, forced and natural convection. The relative direction of the buoyancy force and the externally forced flow is important. Where the externally forced flow is in the same direction as that of the buoyancy force, the thermal energy transport is assisting (or aiding) combined convection. Similarly, when the externally forced flow is in a direction directly opposite that of the buoyancy force, the thermal energy transport is opposing combined convection. Relatively little research exists for combined convection as compared with pure forced or pure natural convection.

    Work in Progress: Utilization of disk-type thermistor heat transfer models for measuring convective heat transfer coefficients for natural and combined convection. Development of a modified Reynold’s number which incorporates a characteristic velocity for natural convection.
  3. Analytical and Experimental Techniques Associated with Time Varying and Steady State Fluid and Thermal Systems, Components, Processes and Measurements. The formulation and development of simplified theoretical models that are usually more agreeable to closed-form analytical solution, and yield insight into the relevant physical parameters of transient characteristics of the phenomena.

    Research in Progress: Predicting Steady-State conduction error and transient lag error in temperature measurements; bulk fuel temperature in fuel tanks and fuel delivery systems; evaporative emissions from fuel tanks based on thermal loading parameters.