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The spacer represents an essential part in the nuclear fuel rod. Spacer grid with mixing vanes in fuel rod bundle of nuclear reactor core has a significant impact on heat transfer performance in downstream to grid spacer. Grid Spacers are located on the nuclear fuel rod assembly to hold suitable clearance among the rods in a bundle. The objective of this paper is to study the enhanced heat transfer performance of R134a at supercritical pressure 4.5 MPa near downstream to mixing vane spacer in a vertical channel of annular flow. A spacer of 0.38 blockage ratio with mixing vanes, situated at mid-span of an annular channel is used in the present work. Numerical simulations have been accomplished for spacer with mixing vane and spacer without mixing vane in an annular channel by using commercial CFD (Computational fluid dynamics) code ANSYS Fluent. The present investigation represents the comparative study for spacer with mixing vane and spacer without mixing vane effects on heat transfer and flow field characteristics in a downstream direction for mass flow-rate 0.41469 kg/s and heat flux 160 kW/m². The results indicate that spacer with mixing vane has notable influence on heat transfer performance and flow field characteristics downstream of mixing vane spacer as compared to spacer without mixing vane. Wall temperature fall and increase of coefficient of heat transfer are significantly greater adjacent to spacer downstream. Spacer influence in the improvement of the heat transfer is noted up to distance X/D = 40 downstream and then flow is found as fully developed. [ABSTRACT FROM AUTHOR]

Proper ventilation is an important strategy in the practice of infection control. Hospitals are complex atmospheres that require ventilation for thermal comfort of patients as well as control of harmful pathogens infection emissions. The present study is performed on a hospital at Raipur (21.2514° N, 81.6296° E), India, to analyze the avoidance of airborne infections from the mouth of patient to protect the doctor and other patients in the intensive care unit (ICU) using Computational Fluid Dynamics (CFD) software FLUENT. Incense smoke is used to for capturing velocity field. Twenty seven (27) cases of simulation were executed using different air change per hour (ACH) (6, 9 & 12) and different inlet and outlet positions talking into account the constant inlet temperature (20 °C). The wall temperatures were taken out from ISHRAE handbook for Raipur region. The velocity vector and capturing the flow field were also performed experimentally. All three turbulence model (Standard, RNG & Realizable) predictions have shown to be in good agreement with the experimental data. It can be effectively employed to validate the extensively used k-e model which was commonly used for ICU. [ABSTRACT FROM AUTHOR]

Indoor air quality ventilation diminishes airborne respiratory and other transmission in hospitals. Airflow in associate medical care Unit (ICU) may be provided through natural mean and additionally by the assistance of mechanical ventilation. Natural ventilation might not be enough to satisfy the requirement of ventilation for associate degree ICU. In the present study, numerical simulation of the airflow pattern and contaminant movement using Computational Fluid Dynamics (CFD) has been carried out for multiple bed hospital ICU with different inlet angles to examine path of contaminant transfer in the hospital. The measurement of air velocity is used as an input and standard k-ɛ turbulence model used in simulation work. Grid Independence Test (GIT) of hospital ICU has been carried out using high-quality tetrahedral unstructured mesh. In order to predict CFD simulations accurately, flow pattern has been validated using model of ICU with four bed and patient occupied with light source. Results shows that increasing rate of air flow change decreases the mean age of air. Importance of outlet position is high for transfer of contaminant particle from ICU. [ABSTRACT FROM AUTHOR]

Pipeline transportation of slurry is being carried out all over the world. Slurry pipeline wear is one of the major problems associated with it. The wear rate of the slurry pipeline depends upon factors such as slurry properties, slurry particle properties, flow properties, and pipeline wall properties. Any change in these properties results in change in pipeline wear rate. There is a need to study the effect of individual properties, for predicting the slurry pipeline life span and also to find the methods to minimize the wear rate. In this review paper, an attempt has been made to discuss the parameters which are believed to be the primary factors that affect material wear rate. Several mechanisms and equations suggested by various researchers for the prediction of wear of materials are also reviewed. Most of the models incorporate the effects of only few parameters involved during the wear process. These equations are specific and valid up to limited operating conditions. No general equation have been evolved which can be used under any operating condition, with better accuracy. This can be attributed to lack of data at microscopic level and also to change in the wear mechanisms under various operating conditions. [ABSTRACT FROM AUTHOR]