Numerical Simulation of Air Flow in Multiple Beds Intensive Care Unit of Hospital

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.

Design and Evaluation of a Fiber Optic Sensor for Particle and Concentration Monitoring in a Contaminated Flow Rig

Optimizing safety and efficiencies is vital to turbomachinery design in the aerospace industry. However, aircraft engines subject to ingestion of airborne particle mixtures of unknown size and concentration have undergone unpredictable malfunction and power losses. Premature damage could be caused by increased erosion rates from mixtures with abrasive material. Similarly, corrosion rates could also increase for mixtures with corrosive material. Further, ingestions with melting points below the combustion exit temperature do melt, adhere to turbine blades, and thereby produce clogs and power losses. Additional blockage could be caused by accumulation of material of fluctuating volumes on blades and vanes. Such malfunction can be prevented by providing these engine systems with an on-board sensor capable of defining the particle size and size distribution and determining instantaneous and cumulative ingestion rates. This study demonstrates the methods used in the design of a fiber optic sensor to size the ingested material and measure its distribution and concentration directly in an engine’s flow path. A high-velocity, high-temperature contamination rig has been designed and built for testing the sensor and evaluating its functionality under engine conditions. Durability tests will be conducted to determine sensor lifespan and assess feasibility of incorporation in current turbomachinery for aircraft protection. Contaminant particle distribution and flow patterns in pipe cross section were studied through laser diffraction and light scattering, to enhance understanding of changes in sensor upon particle impingement.

Intensification of flotation treatment by exposure to vibration

In this paper, an intensification of wastewater flotation treatment by exposure to vibration is studied. Exposure to vibration results in the decrease of air bubble size, increase of air flow through the aerator and more even dispersion of air bubbles in water. This intensifies the aeration process, thus significantly improving the treatment efficiency. A multistage model of flotation kinetics has been applied in order to take into consideration the effects of vibration. The model gives a thorough explanation of the flotation process with consideration of ‘air bubble – contaminant particle’ aggregate formation. A large series of experiments was conducted with paint and varnish industry wastewaters. It is shown that vibroflotation results in an increase of treatment efficiency by up to three times. A comparison of the experimental data with the results of mathematical modeling is presented, showing a good correlation of theoretical and experimental results.

Theoretical Effects of Contaminant Particles on the Lubrication Considering Particle Rotation

The model of a lubrication problem involving a Newtonian fluid with the contaminant particle smaller than the minimum film thickness is developed. The interaction of fluid and particle is considered in the model. The behavior of a particle in the lube oil is also studied. The lube oil is regarded as the continuum phase, and the lubrication problem is solved by the modified Reynolds equation to determine the film pressure and velocity. The dynamics of a particle in the lubricant are studied using Newton’s second law to determine the particle velocity, angular velocity and displacement. The effects of the particle motion including translation and rotation on lubrication characteristics are analyzed. The effect of relative velocity between particle and oil on the pressure is also discussed. The results indicate that the particle motion has a significant effect on the film pressure distribution. When the particle velocity is lower than the film velocity, the motion of particle causes a significant pressure increase. This high pressure only lasts a short time if the particle rotation is neglected. However, when considering the particle rotation, the high pressure will last a much longer time.