Search results

The purpose of this paper is to overview successful approaches to the computational simulation of real fluid (R744 – carbon dioxide (CO₂)) flow within an ejector is presented. Important issues such as the ejector geometry and its optimisation, the adapted equations of state and the proposed models of the process, fluid parameters, etc., are examined and critically discussed. Whenever possible, the discussed models are experimentally validated. In the conclusion, some trends in future research are pointed out.

Flow within CO₂ ejector is generally transcritical and compressible. Models existing in the literature are shortly described and critically compared. Whenever possible, those models were validated against the experimental data. In a model validation process, the primary and secondary mass flow rates as well as the pressures at the selected points in the mixing section and diffuser were compared, showing a satisfactory agreement between experimental and computational results.

Developed CO₂ ejector flow models are tested in few industrial applications. All these initiatives bring solutions which are interesting and very promising from technological point of view.

This is an extensive overview of successful approaches to computational simulation of the real fluid (R744 – CO₂) flow within ejector. It brings many useful information.

Immersive virtual reality (IVR) has been frequently proposed as a promising tool for learning. However, researchers have commonly implemented a plethora of design elements in these IVR systems, which makes the specific aspects of the system that are necessary to achieve beneficial outcomes unclear. Against this background, this study aims to combine the literature on presence with learning theories to propose that the ability of IVR to present 3D objects to users improves the presence of these objects in the virtual environment compared with 2D objects, leading to increased learning performance.

To test this study’s hypotheses, the authors conducted a 2 (training condition: approach vs avoid) x 2 (object presence: high vs low) between-subjects laboratory experiment that used IVR with 83 female participants.

The results support this study’s hypotheses and show that training with high object presence leads to greater reactions to cues (chocolate cravings) and improved health behaviour (chocolate consumption).

This study shows that increased object presence leads to unique experiences for users, which help reinforce training effects. Moreover, this work sheds further light on how immersive computer technologies can affect user attitudes and behaviour. Specifically, this work contributes to IVR research by showing that learning effects can be enhanced through an increased degree of object presence.