A Computational Study of the Distribution of Particles in a Lab-Scale CFB Boiler

When two-fluid modeling is used to predict riser flows there have been difficulties in predicting the solids hold up in risers represented by the correct pressure drop profile. A way of encountering this inherent problem in current Eulerian-Eulerian CFD modeling is to approximate the actual particle size distribution by using more particle phases instead of the current practice of using one mean diameter. For the lab-scale CFB investigated, CFD simulations show that a mal-distribution occurs in the CFB; the larger particles are retained in the riser, whereas the intermediate and small particles are distributed both in the return leg and the riser. Simulations using an altered particle size distribution, i.e. a larger amount of large particles, show significant improvements in the pressure profile in the bottom part of the riser

“We try to give a good life to the children”-refugee parents and ECE professionals experiences of the early childhood education partnership in Norway

IntroductionChildren in Europe and Norway grow up in an increasingly culturally diverse society. As of 2022, 20% of children in Norwegian Early Childhood Education (ECE) institutions have a minority background. It is essential for parents and ECE professionals to work together to ensure a good start for these children. The partnership between the ECE institutions and parents is a statutory right and duty, and parents should, on equal terms, participate and influence what happens in the ECE institutions. However, research has shown a wide variation in how ECE professionals create partnerships with minority and refugee parents, and many find working with this group of parents challenging. This article explores the experiences of the interactions and encounters between refugee parents and ECE professionals in a Norwegian ECE setting. The aim is to analyze the tensions in this partnership and provide insights into these encounters, negotiation processes and their experiences.MethodologyThe study is based on semi-structured interviews with twelve refugee parents, interviews with six pedagogical leaders, and one kindergarten manager. Additionally, fieldwork was conducted in one ECE institution to provide contextual depth.ResultsThe data is analyzed thematically using an inductive research design. Through this analysis, three prominent themes emerged: 1) Barriers, 2) “Norwegianness”, and 3) Trust. The findings highlight the importance of trust in children’s care and the ECE institution’s safety. At the same time, refugee parents emphasize education as a key to a promising future in Norway and value the education aspect of ECE institutions as high. Communication and language barriers pose an extra burden or stress for both ECE professionals and refugee parents. “Norwegianness” as a cultural norm within ECE institutions is linked to the values, norms, and cultural capital valid within the ECE institution.DiscussionThe findings are discussed within the theoretical frameworks of cultural capital and power relations and critical pedagogy. The interactions and encounters between refugee parents and ECE professionals show tensions arising from differences in cultural norms and understandings. In summary, this article explores the challenges posed by cultural diversity in ECE institutions and argues for using cultural sensitivity to foster more flexibility in these encounters to enhance inclusion and belonging in ECE institutions

Wave Influenced Wind and the Effect on Offshore Wind Turbine Performance

In this paper the effect of wave influenced wind on offshore wind turbines is studied numerically. The wave is seen as a dynamical roughness that influences the wind flow and hence the wind turbine performance. An actuator line representation of the NREL's 5 MW offshore baseline wind turbine is placed in a simulation domain with a moving mesh that resolves the ocean waves. These wave influenced wind turbine simulations, WIWiTS, show that the wave will influence the wind field at the turbine rotor height. Both the produced power and the tangential forces on the rotor blades will vary according to the three different cases studied: wind aligned with a swell, wind opposing the swell and wind over a surface with low roughness (no waves).publishedVersio

HySafe Standard benchmark Problem SBEP-V11: Predictions of hydrogen release and dispersion from a CGH2 bus in an underpass

One of the tasks of the HySafe Network of Excellence was the evaluation of available CFD tools and models for dispersion and combustion in selected hydrogen release scenarios identified as “standard benchmark problems” (SBEPs). This paper presents the results of the HySafe standard benchmark problem SBEP-V11. The situation considered is a high pressure hydrogen jet release from a compressed gaseous hydrogen (CGH2) bus in an underpass. The bus considered is equipped with 8 cylinders of 5 kg hydrogen each at 35 MPa storage pressure. The underpass is assumed to be of the common beam and slab type construction with I-beams spanning across the highway at 3 m centres (normal to the bus), plus cross bracing between the main beams, and light armatures parallel to the bus direction. The main goal of the present work was to evaluate the role of obstructions on the underside of the bridge deck on the dispersion patterns and assess the potential for hydrogen accumulation. Four HySafe partners participated in this benchmark, with 4 different CFD codes, ADREA-HF, CFX, FLACS and FLUENT. Four scenarios were examined in total. In the base case scenario 20 kg of hydrogen was released in the basic geometry. In Sensitivity Test 1 the release position was moved so that the hydrogen jet could hit directly the light armature on the roof of the underpass. In Sensitivity Test 2 the underside of the bridge deck was flat. In Sensitivity Test 3 the release was from one cylinder instead of four (5 kg instead of 20). The paper compares the results predicted by the four different computational approaches and attempts to identify the reasons for observed disagreements. The paper also concludes on the effects of the obstructions on the underside of the bridge deck