ABSTRACT
Impinging jet has been widely used to increase the heat and mass transfer rate between the impinging fluid and the impingement surface. It has also been implemented in drying of thin and flat products. Owing to its high heat and mass transfer, impinging jet drying is usually implemented in a short period to avoid overheating the drying materials. Despite its apparently simple geometry, the characteristic of the impinging jet flow is complex and has been the subject of numerous studies. To expedite further development and encourage wider adoption of this impinging jet drying method, it is necessary to extract the essential information on its basic mechanism and the current development stage of this drying method. This chapter is intended to provide a comprehensive overview of the basic mechanism of jet impingement, heat transfer of impinging jet, effect of intermittency and pulsation to the heat transfer performance of impinging jet and the application of intermittent and pulsation impinging jet on thermal drying. In addition, numerous available correlations to estimate the heat transfer coefficient of jet impingement will be presented to assist quick process design. This chapter is expected to serve as basic guideline in the adoption of intermittent or pulsation impinging jet on thermal drying.
