Fred Ahrens Professor School of Mechanical Engineering Ph.D., University of Wisconsin - Madison,    1971

Dr. Ahrens obtained his B.S and M.S. degrees in Mechanical Engineering from Case Institute of Technology and the University of Idaho, respectively, and received his Ph.D. from the University of Wisconsin - Madison in 1971. His graduate education emphasized the thermal/fluid sciences. Dr. Ahrens' career has been divided between industrial, national laboratory and academic assignments. The academic experience has included both traditional Mechanical Engineering (University of Missouri-Columbia) and non-traditional Paper Science (Institute of Paper Chemistry/Institute of Paper Science and Technology) components.

Dr. Ahrens has been active at the local and national levels in the American Society of Mechanical Engineers, and is currently on the Water Removal Committee of the Technical Association of the Pulp and Paper Industry. He has served as a Paper Drying session organizer (1992, 2000) and on the awards committee (2000), for recent conferences in the International Drying Symposium series. He received an award for Best Paper published in Drying Technology: An International Journal (1986-87), presented at the 6th International Drying Symposium (Versailles, September 1988).

Research Summary

Dr. Ahrens' most recent industrial and academic research experience is in the papermaking processes area and includes extensive work in forming/headboxes, pressing, non-compressive dewatering, and drying. The industrial research (ten years) focussed on processes for production of tissue and towel. At IPST, he is a Professor of Engineering and is the Unit Leader, Water Removal Research. He and his co-workers are presently working on ways to increase the productivity of current paper machine dryer sections, developing new high-intensity drying processes (with emphasis on Pulsed Air Impingement Drying), and evaluating/developing new microwave drying technology. The research includes use of laboratory and computer simulation techniques to study pressing, dewatering and drying fundamentals. Dr. Ahrens is also involved in Acoustic Separation Technology research (use of ultrasonics for whitewater clarification, fiber fractionation, and pulp thickening).

Typically, Dr. Ahrens' paper industry-related projects emphasize one of four aspects:

• Understanding of Fundamental Transport Mechanisms and Phenomena (e.g., liquid and vapor permeability, and heat transport, in partially-saturated paper webs; water absorption and wicking in paper towels)
  
• Understanding/Development of New/Improved Processes, Technologies or Equipment (e.g., headbox flow analysis and design; foam forming; capillary and displacement dewatering; impulse, through-air and high-intensity drying)
  
• System Analysis, Design and Optimization (e.g., Yankee dryer computer modeling)
  
• Improving Product Performance via Understanding/Altering the Process (e.g., effect of papermaking process alternatives on bulk and absorbency of paper towels).

Dr. Ahrens has considerable non-paper-related research experience, as well. This work has been primarily in the area of thermal/energy systems, and has dealt with a wide variety of applications, including nuclear reactor safety, refrigeration and air conditioning, pulse combustion burners for heating, and compressed air energy storage power systems. The work has resulted in development of significant expertise in computer-aided modeling, simulation and optimization.