Computational fluid dynamics study of pull and plug flow boundary condition on nasal airflow

The recent advances in the computer based computational fluid dynamics (CFD) software tools in the study of airflow behavior in the nasal cavity have opened an entirely new field of medical research. This numerical modeling method has provided both engineers and medical specialists with a clearer understanding of the physics associated with the flow in the complicated nasal domain. The outcome of any CFD investigation depends on the appropriateness of the boundary conditions applied. Most researchers have employed plug boundary condition as against the pull flow which closely resembles the physiological phenomenon associated with the breathing mechanism. A comparative study on the effect of using the plug and pull flow boundary conditions are evaluated and their effect on the nasal flow are studied. Discretization error estimation using Richardson's extrapolation (RE) method has also been carried out. The study is based on the numerical model obtained from computed tomographic data of a healthy Malaysian subject. A steady state Reynold averaged Navier–Stokes and continuity equations is solved for inspiratory flow having flow rate 20 L/min representing turbulent boundary conditions. Comparative study is made between the pull and plug flow model. Variation in flow patterns and flow features such as resistance, pressure and velocity are presented. At the nasal valve, the resistance for plug flow is 0.664 Pa-min/L and for pull flow the value is 0.304 Pa-min/L. The maximum velocity at the nasal valve is 3.28 m/s for plug flow and 3.57 m/s for pull flow model

Intensified equipment for producing high purity mtbe

MTBE is produced from reaction between isobutene and methanol . HP MTBE is obtained from purification of industrial grade MTBE to purity of ≥ 99.7 wt% . HP MTBE is used in agriculture, pharmaceutical, cosmetics, food and chemical intermediates. Industrial grade MTBE contain contaminants i.e., isobutene, tertiary butanol, methanol, methyl sec-butyl ether or water. Analysis of 11 components in IG MTBE founds 41 azeotropes. 7 related to MTBE. Few options to break azeotrope i.e., pressure swing distillation, extractive distillation, membrane etc. These approaches are however complex

Experimental and numerical studies of porous media combustion in micro burner

Porous media combustion has been key point of interest for researchers from past couple of decades due its numerous advantages, such as remarkable low emission levels without compromising thermal efficiency. In this present work, dual layered micro burner was built with predefined thickness of reaction and preheat layer. Reaction layer was made up of alumina (discrete type) while preheat layer porcelain (foam type) material. Burner was successfully built to undergo both surface and submerged flames. A concept of equivalences ratio was enabled since its premixed combustion with natural air as one of the inlet along with butane. Trials were not just restricted at stoichiometric ratio but also carried out up to ultra-lean region. Additionally, numerical simulation was performed using commercially available computational fluid dynamics package so that porous media combustion phenomenon can be better analyzed and predicted. Finally, Thermal efficiency was calculated at critical equivalence ratios and emission parameters such as NOx and CO was continuously monitored which were under controlled limits

Overview of the important factors influencing the performance of eco-friendly brake pads

The braking system is a crucial element in automotive safety. In order for the braking mechanism to function effectively, the brake pads’ durability as well as quality are crucial aspects to take into account. A brake pad is a part of a vehicle that holds the wheel rotation so that braking can occur. Asbestos, which is harmful to human health, is a raw material that is recently being widely used as a material mixture for the manufacturing of brake pads. Many efforts have been made by researchers to find other natural alternative materials to replace the use of asbestos. Natural materials that have received much attention and research include coconut fiber, wood powder or flour, bamboo fiber, shell powder, etc. This review paper focuses on analyzing the main parameters that affect brake pad performance. The composition of filler and fiber types of reinforcement for polymer composites is discussed. Previous studies’ information on the fabrication and testing of brake pads are also highlighted. Furthermore, the findings of this review can provide researchers and academicians with useful information and points to consider for further research