Spray cleaning of surfaces affected by a film of soiling is a daily task in food and pharmaceutical industry. Improvements in the cleaning process are directly linked to a reduction of cost associated with the cleaning due to reduced downtimes and reduced amount of cleaning agents (cost for conditioning or disposal). In this project an improvement of the cleaning process is addressed by using virtual engineering to develop a novel approach for the design of efficiency optimized cleaning nozzles. The planed virtual design and optimization process enables the systematical development of cleaning nozzles according to the specific need within their application. Here, a nearly unlimited number of design changes can be tested in a virtual environment with a manageable effort. This is expected to have a significant and positive impact on the quality of nozzle optimization and consequently on the cleaning efficiency of the nozzles.
Due to the complexity of the entire process the planned activities are restricted to the system defined by nozzle, freestream and surface to be cleaned. Within this closed system the liquid jet interacts with the surface to be cleaned whereas fluid dynamic effects due to the transfer of momentum from the freestream to the surface or soiling are observed. The process is inducing forces which result in mechanical tensions within the film of soiling. Once a critical threshold of the tensions is reached a partial damage of the soiling occurs leading to an ablation of the former. To account the scientific and technical challenges within this approach in a reasonable manner the fundamental mechanical knowledge connected with Mohr’s circle will be assigned to the cleaning behavior of film soiling. In combination with the fundamental balance equations of fluid mechanics a sound basis for the virtual engineering of efficiency optimized low pressure cleaning nozzles is formed.
The IGF project presented here by the Research Association of the Industrial Association for Food Technology and Packaging (IVLV e.V.) is funded by the Federal Ministry for Economic Affairs and Energy via the AiF as part of the program for the promotion of industrial community research (IGF) based on a decision of the German Bundestag.