Abstract: Commercial foodservice industry is evolving at a rapid pace. Along with the need to continuously improve equipment performance, industry is looking at innovative ways to prepare, cook and store food. Lowering energy consumption and maintaining higher quality standards for food dictates cooking food efficiently and faster than ever before while preserving its essential taste. Cooking and storing food at elevated temperatures with forced air is one of the most efficient ways to meet the demands of the industry.

Heat transfer coefficients in cooking food with impinged air have known to reach values in the range of 150 W/m²K - 250 W/m²K as compared to under 100 W/m²K using traditional approaches. To further improve heat transfer, a deep understanding of how jet impingement works, is essential. By analyzing and studying air impingement, performance improvement in foodservice equipment can be achieved. Computational Fluid Dynamics (CFD) simulation is used in the research to analyze turbulent jet impingement for single and multiple nozzle arrangement. To validate model, the simulation is verified against known experimental results.

The simulation is further improved by analyzing interdependencies between different variables such as nozzle velocities, H/D ratio and S/D ratio. It was found that for H/D ratios ranging between 6 and 8, nozzle velocities over 20 m/s provide a large percentage increase in heat transfer. Higher S/D ratios result in higher local heat transfer coefficient values near stagnation point. However, increased spacing between the neighboring jets results in reduced coverage of the impingement surface lowering the average heat transfer. Lower H/D ratios result in higher heat transfer coefficient peaks. The peaks for all three nozzles are more uniform for H/D ratios between 6 and 8. For a fixed nozzle velocity, heat transfer coefficient values are directly proportional to nozzle diameter. For a fixed H/D and S/D ratio, heat transfer rate and average impingement surface temperature increases as the nozzle velocity increases until it reaches a limiting value. Further increase in nozzle velocity causes drop in heat transfer rate due to ingress of large amounts of cold ambient air in the control volume.

The research concludes with case study of conveyor ovens. For researchers interested in taking this work further, a more complicated transient analysis of entire conveyor oven can be performed. The author has identified high impact key parameters for a conveyor oven. Further work can be done by varying additional parameters as outlined in the research to optimize the performance of jet impingement systems.

Biography: Dr. Shevade is a Director of Engineering at Welbilt, Inc. a leading multi-national commercial food service equipment manufacturer, headquartered in New Port Richey, Florida. He is responsible for leading all engineering functions of company’s Hot Holding Group including research & development, new product introductions and sustaining engineering.

Shan received his Bachelor of Engineering Degree from the University of Mumbai, India. He received both Master’s and Ph.D. Degrees in Mechanical Engineering from the University of South Florida (USF) in Tampa, Florida. Shan also holds an advanced post-graduate diploma in software technology and computer programming. While completing his master’s degree, Shan worked on NASA funded research for magnetocaloric refrigeration system. During his doctoral degree, Shan focused his work on analysis of air jet impingement and turbulent fluid interactions.

Shan has more than 13 years of experience working in engineering roles of increasing responsibilities in the fields of aerospace, defense, power generation and food service industries. His work in Computational Fluid Dynamics has resulted in multiple journal publications and presentations at several engineering conferences throughout the United States.