OBJECTIVES To use computational fluid dynamics (CFD) for evaluating and understanding the performance of the high-dose disposable Twincer™ dry powder inhaler, as well as to learn the effect of design modifications on dose entrainment, powder dispersion and retention behaviour. METHODS Comparison of predicted flow and particle behaviour from CFD computations with experimental data obtained wit...

Shape optimization of the airfoil with high aspect ratio of long endurance unmanned aerial vehicle (UAV) is performed by the multi-objective optimization technology coupled with computational fluid dynamics (CFD). For predicting the aerodynamic characteristics around the airfoil the high-fidelity Navier-Stokes solver is employed and SMOGA (Simple Multi-Objective Genetic Algorithm), which is dev...

The maximum lift that can be used in a feather valve for a particular application is limited by the valve failures that occur if the lift is too high. This limit ~as been increased by testing valves with a high lift and investigating the resulting failures. This has shown that the primary cause of failure is damage caused to the strip by impact of the strip on the guard. As a result of this wor...

In the continuous gas lift operation, compressed gas is injected into the lower section of tubing through annulus. The produced liquid flow rate is a function of gas injection rate and injection depth. All the equations to determine depth of injection assumes constant density for gas based on an average temperature of surface and bottomhole that decreases the accuracy of gas lift design. Also g...

Particulate matter (soot) emissions from combustion processes have damaging health and environmental effects. Numerical techniques with varying levels of accuracy computational time been developed to model soot formation in flames. High-fidelity models come a significant cost as result, accurate modelling becomes numerically prohibitive for simulations industrial devices. In the present study, ...

It is necessary to meet increasingly stringent emission standards of IC engines, reducing the values. While improving engine parameters and combustion chamber geometries can reduce emissions, also research continues for alternative fuels. Diesel production from waste cooking oils has advantages in terms recycling, environment, cost. Waste be used as fuel with minor modifications. oil-based biod...

One of the important problems in reducing of pollutant emission from DI and IDI diesel engines is trade-off  between soot and NOx. Split injection is one of the most powerful tools that makes the chance to shift the trade-off curve closer to origin.  At the present work, the effect of split injection on the combustion process and emissions of a cylinder IDI diesel engine under the specification...

As a result of the durability problems associated with the first Abrams-Lucas mitral valve, a redesigned model has recently been introduced into limited clinical trials. The new valve was subjected to in-vitro pulsatile flow studies, and measurements were made of mean diastolic pressure gradient and volume of reflux on closure. Similar measurements were made on other mitral valve prostheses of ...

1. Abstract Nowadays, the use of computational fluid dynamics (CFD) in the design of valves is very common. Despite the continuing growth of computing capability, the computational cost of complex three-dimensional CFD analysis of butterfly valve maintains high, therefore, the CFD analysis-based optimization becomes more time-consuming and computational expensive. In this paper, a comparative s...