Norasikin Mat Isa

A Study on Contact Angle and Surface Tension on Copper-ABS for FDM Feedstock

This paper presents the development of a new Copper-ABS feedstock material by the injection molding machine. The material consists of copper powder filled in an acrylonitrile butadiene styrene (ABS) binder and surfactant material. In this study, the effect of metal filled ABS and binder content on the contact angle and surface tension was investigated experimentally. The detailed formulations of compounding ratio with various combinations of a new Copper-ABS feedstock was done by volume percentage (vol. %). Based on the result obtained, an increment by vol. % of copper filler in ABS effected on contact angle and surface tension results. With highly filled copper content in ABS composites increase the surface tension value. It can be observed that, the tendency of the liquid surface that allow to resist an external force in PMC material through an injection molding process.

Investigation of Boiling Heat Transfer and Flow Regimes in a Heat Exchanger

Experimental and numerical simulation of heat transfer and flow regimes for vertical flow across horizontal tubes are presented for mass flow rate in the range 0.03 – 0.17 kg/s and heat fluxes in the range 1.07–1.35 kW/m2. The tubes had a diameter of 9.75 mm and a pitch to diameter ratio of 1.85. The CFX version 14.0 from ANSYS was used to predict the flow regimes and the temperature distribution in the tube bundles. These data and the predictions from numerical simulation were compared with the data available in the literature. It is found that the circulation zone in the shell becomes bigger as the mass flow rate is increases. The flow patterns identified in this experiment are bubbly, intermittent and annular flow. These data agrees well with the published data.

Experimental Study of Splitting Device for Horizontal Pipeline

The flow distribution within a reduced scale model pipeline to study and determine the best splitting device for a horizontal pipeline through experiments were conducted. In this research, five splitting devices are designed and tested on the model rig. Out of five, only one splitting device has been chosen that achieved the objective the best; to improve airflow to be a homogeneous flow in the pipe, or at least reducing and improving from the roping condition. The process of selecting the best device had been done through qualitative analysis of velocity profile and airflow distribution obtained from Pitot Tube measurements, besides the airflow pattern and behavior through PIV results.

Flow Separation Prediction in a Single-Phase Flow in an Inline Tube Bundles

The vertical single-phase flow was studied on the shell side of a horizontal tube bundle. In the present study, CFX version 14.0 from ANSYS was used to predict the flow regimes in the two tube bundles; i.e. the 19 mm and 38 mm arranged in an in-line configuration with a pitch to diameter ratio of 1.32. The simulations were undertaken to inform on how the fluid flowed within the tube passages in different tube bundle diameter that gives different gaps between the tubes, where the fluid must pass. The results show that the maximum gaps between the tubes have no clear effect to the flow where the flow separation and re-attachment and the average velocity is the same when increasing the tube bundle. This is consistent with other published data.

Computational fluid dynamics simulation of pressure and velocity distribution inside Meniere’s diseased vestibular system

Menieres disease or known as endolymphatic hydrops is an incurable vestibular disorder of the inner ear. This is due to the excessive fluid build-up in the endolymphatic sac which causing the vestibular endolymphatic membrane to start stretching. Although this mechanism has been widely accepted as the likely mechanism of Menieres syndrome, the reason for its occurrence remains unclear. Thus, the aims of this study to investigate the critical parameters of fluid flow in membranous labyrinth that is influencing instability of vestibular system. In addition, to visualise the flow behaviour between a normal membranous labyrinth and dilated membranous labyrinth in Menieres disease in predicting instability of vestibular system. Three dimensional geometry of endolymphatic sac is obtained from Magnetic Resonance Images (MRI) and reconstructed using commercial software. As basis of comparison the two different model of endolymphatic sac is considered in this study which are normal membranous labyrinth for model I and dilated membranous labyrinth for model II. Computational fluid dynamics (CFD) method is used to analyse the behaviour of pressure and velocity flow in the endolymphatic sac. The comparison was made in terms of pressure distribution and velocity profile. The results show that the pressure for dilated membranous labyrinth is greater than normal membranous labyrinth. Due to abnormally pressure in the vestibular system, it leads to the increasing value of the velocity at dilated membranous labyrinth while at the normal membranous labyrinth the velocity values decreasing. As a conclusion by changing the parameters which is pressure and velocity can significantly affect to the instability of vestibular system for Menieres disease.

Flow behaviour in normal and Meniere's disease of endolymphatic fluid inside the inner ear

Menieres disease is a rare disorder that affects the inner ear which might be more severe if not treated. This is due to fluctuating pressure of the fluid in the endolymphatic sac and dysfunction of cochlea which causing the stretching of vestibular membrane. However, the pattern of the flow recirculation in endolymphatic region is still not fully understood. Thus, this study aims to investigate the correlation between the increasing volume of endolymphatic fluid and flow characteristics such as velocity, pressure and wall shear stress. Three dimensional model of simplified endolymphatic region is modeled using computer aided design (CAD) software and simulated using computational fluid dynamic (CFD) software. There are three different models are investigated; normal (N) model, Menieres disease model with less severity (M1) and Menieres disease model with high severity (M2). From the observed, the pressure drop between inlet and outlet of inner ear becomes decreases as the outlet pressure along with endolymphatic volume increases. However, constant flow rate imposed at the inlet of endolymphatic showing the lowest velocity. Flow recirculation near to endolymphatic region is occurred as the volume in endolympathic increases. Overall, high velocity is monitored near to cochlear duct, ductus reuniens and endolymphatic duct. Hence, these areas show high distributions of wall shear stress (WSS) that indicating a high probability of endolymphatic wall membrane dilation. Thus, more severe conditions of Menieres disease, more complex of flow characteristic is occurred. This phenomenon presenting high probability of rupture is predicted at the certain area in the anatomy of vestibular system.

Study the velocity and pressure exerted in front of the filter surface in the kitchen hood system by using ANSYS

Commercial kitchen hood ventilation system is a device used to capture and filtered the plumes from cooking activities in the kitchen area. Nowadays, it is very popular in the industrial sector such as restaurant and hotel to provide hygiene food. This study focused at the KSA filter part which installed in the kitchen hood system, the purpose of this study is to identify the critical region which indicated by observing the velocity and pressure of plumes exerted at of KSA filter. It is important to know the critical location of the KSA filter in order to install the nozzle which will helps increase the filtration effectiveness. The ANSYS 16.1 (FLUENT) software as a tool used to simulate the kitchen hood systems which consist of KSA filter. The commercial kitchen hood system model has a dimension 700 mm width, 1600 mm length and 555 mm height. The system has two inlets and one outlet. The velocity of the plumes is set to be 0.235m/s and the velocity of the inlet capture jet is set to be 1.078m/s. The KSA ...

Effects of changing airfoil aerodynamic characteristics on turning diffuser performances

Combining both turning and diffusing activities by using 3-dimensional turning diffuser offer more advantages as compared to bend-diffuser systems. However, adverse pressure gradient and curvature design of turning diffuser itself will result in existence of secondary flow at the inner wall and both left and right wall region, which will disrupt turning diffuser performance. Introduction of baffle has successfully proven able to improve the performance of 3-dimensional turning diffuser in terms of both pressure recovery and flow uniformity using experimental approach. Preliminary design airfoil referred to previous study was used, and the results were used to validate present study simulation work. Aerodynamic characteristic of the airfoil were varied and series of simulation were conducted to study the effects of changing aerodynamic characteristics of an airfoil on turning diffuser performance. Optimum parameters proposed in this study have successfully improved 3-dimensional turning diffuser performanc...

Numerical Study of Flow Separation and Pressure Drop for Flow Past Staggered Tube Bundles

The vertical single-phase flow was studied on the shell side of a horizontal tube bundle. In the present study, CFX version 14.0 from ANSYS was used to predict the flow regimes in the 19 mm diameter in staggered configuration with a pitch to diameter ratio of 1.32. The simulations were undertaken to inform on how the fluid flowed within the tube passages. The results show that the tube bundle arrangement in a heat exchanger does effect to the flow separation and re-attachment points. This is consistent with other published data.

Pressure Distribution around Mixing Blades in Biodiesel Reactor Using Computational Fluid Dynamics (CFD)

This paper presented simulation analysis of stress distribution along a mixing blades propeller used in biodiesel reactor tank. The mixing blade types used are: (1) three bladed mixing propeller, (2) pitch turbine blade and (3) Rushton blade. ANSYS FLUENT software was used to run the simulation. The maximum stress occurs when using three bladed mixing propellers type. The minimum stress occurs when using the Rushton blade. Therefore, the Rushton blade is the best blade used for biodiesel reactor. Stress concentration is observed at the fillet for all blade types. The selection of the right type mixing blade can improve the biodiesel production and lower the maintenance cost. The result obtained from the simulation is agreed well with the published data.