TS 23: Mixing processes in confined turbulent opposing streams

Student Name: Saravanan S/O Ayyavoo

Advisor:  Prof. Arun S Mujumdar; Co-advisor: Wang Shijun

Abstract: Opposing jets or streams of fluid ( gas or liquid) that impinge head-on in a confined chamber or in a flowing stream provide conditions for rapid mixing. Opposing jet configurations have found a wide range of industrial applications in mixing, absorption, drying, combustion, mixing head for reaction injection molding, extraction, biomedical devices etc.. This project aims at studying the flow and mixing characteristics of a three-dimensional in-line mixer ( i.e. with no moving parts)using round opposing jets perpendicular to and flush with the internal wall of a cylindrical tube. Air streams of different temperature impinge normally and the development of the temperature profile in the exit tube is measured as an indicator of the degree of mixing. A CFD code ( Fluent 6.1) will be used to predict the flow and temperature fields and the mixing index as functions of the flow and geometric parameters. 

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TS 24: A Novel vibrating drum near-atmospheric freeze dryer

Student Name:   Zhao Gui Zhong

Advisor:  Prof. Arun S Mujumdar; Co-advisor: Mr S .M.   Atiqure Rahman  

Abstract: This experimental project will examine and try to correlate the effects of various  particle, vibration and equipment parameters on mixing, heat transfer to wall and drying with radiative and conductive heat input for a bed of particles placed in a vibrating drum subjected to vertical or oblique vibration. This is the first phase of a cold model study  to provide important information for the next phase which will examine use of adsorbents  and application of  vacuum at low temperatures to accomplish atmospheric freeze drying in a novel dryer configuration.

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TS 26: Fuel cell performance simulation

Student: Chen Zhenhao

Supervisor: Prof. A S Mujumdar (NUS); Co-Supervisor: Poh Hee Joo, IHPC

Abstract: In view of ever increasing levels of environmental pollution and thus a desire to replace the fossil-fuel-based economy with a cleaner alternative, the polymer electrolyte membrane fuel cell (PEMFC) has in recent years emerged as a prime candidate for automotive, portable and stationary applications. These fuel cells convert hydrogen or hydrocarbon fuels directly into electricity. High efficiency, as the fuel cell is not limited by the Carnot-efficiency, low emissions, silent operation, no moving parts and a scalable system, number among the main advantages of fuel cells.

Three important issues for the fuel cell performance are:

•  Gas management – due to mass transport limitations of hydrogen and oxygen to anode and cathode electrode, especially at higher current density.

•  Water management – to prevent flooding (especially cathode) while maintaining membrane at “right” humidity level for ion conduction.

•  Thermal management - to ensure that the heat generated throughout the cell, in particular at the active layer of the cathode, is removed by adequate cooling of the cell.

The objective of this study the various transport processes and chemical reactions occurring within the heart of fuel cell and subsequently enhance the fuel cell performance. Simulation of the transport processes will be carried out using a commercial CFD software.

Objectives:

•  To understand the basic operation of Polymer Electrolyte Fuel Cell (PEMFC) and the related transport phenomena that occurs within the heart of fuel cell (anode, cathode and membrane electrode assembly).

•  To carry out computational study of a tapered serpentine flow channel with both steady and pulsating flow, in order to investigate the feasibility of mass transport enhancement using the new pulsating flow along the channel.

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TS 27: Study of nano-fluids for potential application in electronic cooling

Student: Goh Weihao  

Supervisor: Prof. A S Mujumdar ; Co-Supervisor: Wang Xiangqi  

Abstract: Nano-fluids are a new class of solid-liquid composite materials by suspending solid nano-particles in base fluids, which was first proposed by Choi (ANL, USA) in 1995. In recent years nano-fluids have attracted great interest due to their greatly enhanced thermal properties such as anomalously high thermal conductivity. Preliminary studies show that nanofluids provide very high convective heat transfer characteristics. This project is designed to evaluate nanofluids experimentally and numerically by examining forced convective heat transfer characteristics of such fluids in a mini-channel. Their potential for electronic cooling and other thermal cooling application will be evaluated.

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TS 29: Analysis of drag on jack-up rigs used in off-shore drilling

Student: Adil B Shoib

Supervisor: Prof. A S Mujumdar (NUS); Co-Supervisor: Zhang Baili, IHPC

Abstract: The jack-up units is one of widely used offshore oil drilling tools. The leg of oil jack-up rigs under water experiences the drag force due to the sea current flow. Accurate calculation of drag force is very important to the structure design of the leg of oil jackup rigs. The main objectives of this study are to provide accurate prediction of drag coefficient for rig leg component under water by computational fluid dynamics (CFD) simulations.

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