Rockwool (Denmark)

The Dense Discrete Phase Model, DDPM, was used to investigate erosion, caused by the impacts of solid particles, in an industrial cyclone preheater by application of Oka's erosion model. The model predictions of flow pattern and temperature profile were validated by measurements in an industrial cyclone preheater. Then, the erosion model was tested against the results in a lab-scale cyclone reported in the literature. Furthermore, the erosion patterns in the industrial cyclone preheater were predicted by the model. The predicted results were qualitatively matching with the erosion observed in the cyclone. In addition, parametric studies on key operating conditions were performed and the impacts on erosion as well as pressure drop and heat transfer rate were evaluated. The results indicate that gas flow rate and inlet temperature have the greatest influence on erosion. The erosion rate is largely unaffected by solid flow rate and particle size in the studied range.

A hybrid multiphase model (Dense Discrete Phase Model, DDPM) coupled with a k-ω sst turbulence model, which includes gas–solid heat exchange was developed for the simulation of industrial-scale cyclone preheaters operating under high solid loadings. The model results are validated by experimental measurements from an industrial cyclone preheater with a diameter of 1.6 m, with respect to the pressure drop, gas and particle exit temperature, local gas velocity profiles, measured using the LDA, and gas temperature profiles, measured using thermocouple and FTIR. Reasonable agreement between the data from experiments and simulations was obtained. In addition, the major trends, such as changes in the pressure drop, overall heat transfer rate, and flow pattern, caused by the changes in the operating parameters can be captured accurately by the model.

The study investigated possible effects of recording/playback technique and experimental method on assessments of annoyance, loudness and unpleasantness. A possible effect of exposure duration was also studied. Sounds were recorded with two different techniques: monophonic and binaural (dummy-head technique). In addition, they were reproduced with three different techniques: monophonic recordings presented through a loudspeaker system, binaural recordings presented through closed (circum-aural) and completely open (free-of-the-ear headphones. The study adopted three psychometric methods for collecting responses from test-subjects. Fifty-four subjects participated, and three types of sounds were used: everyday restaurant sound, road traffic sound and ventilation sound dominated by low frequencies. Each sound was played back at three different levels. The results show that there is no significant main effect of recording and playback technique for any of the three perceptual attributes; however, significant interactions between techniques and sounds were found. Since the effect of recording and playback technique differs depending on sound, this finding is of importance for future design of experiments and interpretation of results. The results also show that long-term annoyance and unpleasantness are poorly predicted by short-duration methods.

Full-scale measurements on a mineral melting cupola furnace for stone wool production have been made to investigate the behavior and increase the understanding of mineral melting cupolas. The work includes probe measurements of gas concentration, solid/melt phase and gas temperature, and melt composition at several vertical and radial positions in the cupola. Four types of experiments were conducted: quenching of an operating cupola, sample collection from the hot part of the cupola using probes through the walls, sample collection through a probe inserted from the top of the cupola, and collection of input and output data. The experiments showed the position of the melting zone, porosity, and other characteristics. The probe experiments indicate that the oxygen is consumed approximately 0.3 m above the tuyeres. The top probe experiments gave the temperature profile in the cupola.