Alan Friis

Critical wall shear stress for the EHEDG test method

In order to simulate the results of practical cleaning tests on closed processing equipment, based on wall shear stress predicted by computational fluid dynamics, a critical wall shear stress is required for that particular cleaning method. This work presents investigations that provide a critical wall shear stress of 3 Pa for the standardised EHEDG cleaning test method. The cleaning tests were performed on a test disc placed in a radial flowcell assay. Turbulent flow conditions were generated and the corresponding wall shear stresses were predicted from CFD simulations. Combining wall shear stress predictions from a simulation using the low Re k-e and one using the two-layer model of Norris and Reynolds were found to produce reliable predictions compared to empirical solutions for the ideal flow case. The comparison of wall shear stress curves predicted for the real RFC with the empirical solution showed that the empirical solution gives a good prediction even in the real RFC from a radius of 15 mm and outwards.

Prediction of hygiene in food processing equipment using flow modelling

Computational fluid dynamics (CFD) has been applied to investigate the design of closed process equipment with respect to cleanability. The CFD simulations were validated using the standardized cleaning test proposed by the European Hygienic Engineering and Design Group. CFD has been proven as a tool which can be used by manufacturers to facilitate their equipment design for high hygienic standards before constructing any prototypes. The study of hydrodynamic cleanability of closed processing equipment was discussed based on modelling the flow in a valve house, an up-stand and various expansions in tubes. Results show that cleaning can be efficient in complex geometries even when the critical wall shear stress (determined in uni-axial flow) is not exceeded. This renders the need for considerations concerning three-dimensional flow, the degree of turbulence and the type of flow pattern. The controlling factors for cleaning identified were the wall shear stress and the nature and magnitude of recirculation zones present.

Product development alliances: factors influencing formation and success

Purpose – The objective of this paper is to develop a framework, based on existing literature, for factors influencing the formation and success of product development alliances, and relate this specifically to the food industry.Design/methodology/approach – Case study of a product development alliance, with four partners and an interview survey, with 19 key informants in the Danish food industry.Findings – The nature of the differences between the developed framework for product development alliances in the food industry and theory on alliances in general, indeed seem to rest in the chosen specific context. Companies in the food industry are not forced by external conditions to enter into product development alliances. Therefore, compared to other industries, motivations have to be stronger or risks smaller for them to form such interorganisational relationships. However, once formed, results indicate that success factors are rather universal across industries and types of alliances.Research limitations/...

Consumer-oriented innovation in the food and personal care products sectors: understanding consumers and using their insights in the innovation process.

Abstract: In this chapter, we clarify the concept of consumer-oriented innovation in the food and personal products sectors and define it as a process towards the development of a new product or service in which an integrated analysis and understanding of consumers’ wants, needs and preference formation play a key role . We then outline relevant streams of research that may promote the implementation of consumer-oriented innovation in these sectors. We first review research on understanding consumers, notably on quality perception, associated methods, and their application in innovation processes. We then review research on innovation management, emphasizing the use of consumer insight information in innovation processes. We conclude that a better integration of consumer research and research on innovation management would benefit the innovation process.

Improving the cleaning of tanks.

Publisher Summary Hygiene is important in all processes, because the production cannot be run if it is possible that microbes would infiltrate the process through surfaces and equipment that are used in association with the tank. Contamination on tank surfaces can be fatal to the product quality due to long processing times with nutritious raw materials, where microbial growth leads to discarding large product batches. It has been proved that specific hydrodynamic parameters control cleaning in closed process systems. The fluid flows are important both in production and in cleaning. Computational Fluid Dynamics [“CFD”] is a tool for improving the hygienic design of equipment components and their integration into the process line. The hygienic state of tanks is important in order to avoid contamination of the end product and, therefore, tank cleaning is receiving increasing attention. The specific cases studied comprise dairy- and brewery-process tanks. CFD is used in many applications to model the bulk parameters of fluid flows. Recently, model developments have made it possible to resolve what happens in specific positions on and near walls, which is of interest in the study of cleaning processes. CFD models of tanks exist for purposes of optimizing the operation of processes such as mixing, heating, and cooling.

Co-Rotating Disc Scraped-Surface Heat Exchanger for Food Processing

A laboratory scale prototype of the “Co-Rotating Disc Scraped-Surface Heat Exchanger” (CD-HE), which represents a new design in scraped surface heat exchangers, is currently being investigated. The CD-HE is characterized by having a much larger surface-to-volume ratio than traditional scraped surface heat exchangers and it is especially applicable for processing of viscous food products. Results show that the CD-HE has a high heat transfer capacity and promising Residence-Time-Distributions have been achieved.