Spritzstrahlreinigung
© iStockphoto
Spritzstrahlreinigung

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In spray jet cleaning, the shape and arrangement of the nozzles is particularly important for the cleaning efficiency. They must ensure that all soiled parts are reached during the cleaning process. This is a complex process that must be better understood and optimized through simulation.

Lebensmitteltanks
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Lebensmitteltanks

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One of the most frequently used cleaning processes in the food industry is spray jet cleaning. In this process, a jet is used to remove soiling from the food plant, e.g. also in food tanks.

Simulate Spray Jet Cleaning Without a Grid

SpraySim – Spray Jet Simulation for Periodically Working, Moving Cleaning Nozzles With Innovative, Grid-Free Approach and 2D Efficiency Model

 

Automated cleaning is used in a wide variety of application fields. In the SpraySim project, we focus on Cleaning in Place (CIP) systems from the food, beverage and pharmaceutical industries, in which the cleaning liquid is applied to the soiled surfaces to be cleaned via nozzles as a disintegrated spray jet. Especially in these industries, cleaning cannot be dispensed with, otherwise product quality suffers. In addition, cleaning is sometimes carried out several times a day. Thus, it is a costly process, requires high energy consumption and produces wastewater that is harmful to the environment.

Simulations Save Time, Costs and Experiments

Up to now, empirical approaches based on experiments have been used almost exclusively to increase efficiency. However, experiments can only resolve and understand the cleaning processes to a limited extent. These are good reasons to investigate promising new approaches and research topics in more detail - such as cleaning with discontinuous flow. Flow simulations receive attention in cleaning system development mainly for the nozzle interior, although they generally provide high-resolution insight into the flow field and potentially save time during development. So far, however, there is a lack of efficient simulation models that provide meaningful results with reasonable computational effort.

Düsensimulation
© Fraunhofer IVV/ Fraunhofer ITWM
Vergleich von Experiment und Simulation für eine Vollkegeldüse

Challenges in Combining 3D Spray Jet Simulations With 2D Efficiency Models

The main goal of the project is the numerical simulation of discontinuous spray jets – also for moving nozzles. We follow a grid free approach. In this way, we achieve industry-compatible computation times and subsequently enable optimizations with respect to certain parameters, such as the cleaning efficiency.

Our approach combines 3D spray jet simulations with 2D efficiency models. The basis for validation is an extensive experimental investigation of the flow and the cleaning efficiency by the project partner Fraunhofer IVV in Dresden. 

This results in new challenges from a simulation point of view:

  • Determining the necessary resolution in the grid-free 3D spray jet simulations
  • Integration of a cavitation model for full-cone nozzles
  • Derivation of the 2D efficiency models
  • Optimization of operating parameters

As a result, we expect predictions based on simulations for the first time, in addition to validated models. Especially with regard to suitable pulsation parameters of disintegrated spray jets and their movement during cleaning, they will contribute to a better understanding of the process. The simulation models will be bundled in a software platform. The focus of the software development is on simple usability. This is because small and medium-sized enterprises (SMEs) in particular have greater potential to use the software and thus accelerate the development of new nozzles and significantly improve the efficiency of automated cleaning systems.

Video: Detail Simulation – Impact of a Droplet on a Thin Film of Water#

Impact of a Droplet on a Thin Film of Water