Heat and Mass Transfer from Jet Impingement Flow for Drying Machines

Ali Chitsazan did a doctorate under the supervision of Professor Dr.-Ing. Klepp in the Institute for Energy Research, TH OWL, in cooperation with Leibniz University Hannover, Institute for Multiphase Processes under the supervision of Professor Dr. Ing. Glasmacher. The title of the dissertation is “Heat and Mass Transfer from Jet Impingement Flow for Drying Machines”.

The impingement jets for cooling and drying is used in many industrial applications because of its simple structure and high efficiency, including the drying of lacquered and impregnated paper. Relationships describing the heat and mass transfer for simple nozzles are known, but the parameter diversity and interaction that occurs in industrial processes such as paper drying can only be empirically understood. The flow, the coupled heat and mass transfer, as they occur in the paper drying by impingement jets, will be investigated to allow conclusions about the drying and the force of the impingement jets. For this purpose, the impingement jets are numerically simulated. The numerical model is validated using measured values (single nozzles, nozzle fields, own measurements and literature values). Particular attention should be paid to the correct modeling of turbulent heat and mass transfer. The model investigates the influence and interplay of parameters such as nozzle field design, nozzle pitch, nozzle angle, air flow rate, surface velocity and surface curvature. On this basis, ways can be shown to improve the efficiency of dryers.