The study of air fuel ratio for open furnace MILD combustion of biogas on bluff-body burner

Economical fuel cost is very critical in the heating industry. Lean combustion with high air fuel ratio (AFR) is normally practiced by the industry. Low air fuel ratio or rich combustion will result in unburned hydrocarbons (UHC). UHC is a waste and pollution to the environment. This paper discussed on the modelling of air fuel ratio for the moderate and intense low oxygen dilution (MILD) combustion of biogas on bluff-body burner. Biogas is a low calorific value (LCV) gas which was formulated by using 50% methane, 20% hydrogen and 30% carbon dioxide. AFR is the ratio of air and fuel injected to the combustion chamber. Nozzle outlet size for air and fuel plays important role to determine AFR. In this study, the air and fuel nozzle size ratio used is 23:1. The AFR will be evaluated based on the UHC produced by the combustion. Stoichiometric AFR occurred when zero UHC and zero excess oxygen flow through the EGR pipe. The result shows that when AFR is 4.0, zero UHC was detected in the EGR. UHC in EGR will be waste and create unwanted combustion at the wrong location

Modeling of viscous flows in two-dimensional turbomachinery cascade via viscous-inviscid interaction method

[Abstract]: A two-dimensional time-accurate time-marching viscous flow solver employing the viscous-inviscid interaction method suitable for turbomachinery applications is described. The inviscid main flow solver uses the second-order accurate cellvertex finite-volume spatial discretisation and fourth-order accurate Runge-Kutta temporal integration. The viscous effect due to boundary layer development on the blade surfaces and wakes are modelled using an independent one-dimensional boundary layer subroutine capable of modelling laminar, transition and fully turbulent flows. The solver has been applied to subsonic, transonic and supersonic flow in a cascade of nozzle blades. The results are compared with the experimental data and they showed very good agreemen

An experimental investigation of the effective parameters on wet washing of biodiesel purification

The purity level of biodiesel has a strong effect on fuel properties and on engine life. Therefore, a purification step is necessary. Generally, there are two accepted methods for purifying biodiesel: wet washing and dry washing. In this research, the effective parameters on wet purification of biodiesel were investigated. Three types of biodiesel wash water (tap water, distilled water and water with 3% phosphoric acid), three wet washing temperatures (30, 45 and 60°C), and three levels of water to biodiesel ratios (0.5, 1 and 1.5 v/v) were used. In order to perform the wet washing of biodiesel, a bubble washing technique was used. The catalyst, soap and water residue were considered as the criteria to choose the optimum water washing condition and were measured after the wet washing of crude biodiesel. The results showed that the best condition for catalyst and soap removal from biodiesel are acidified water, a temperature of 60°C and a water to biodiesel ratio of 1.5 (v/v). Also, the least amount of water residue in the final purified biodiesel was observed when using tap water at a temperature of 60°C and a water to biodiesel ratio of 0.5 (v/v)

Development of a Short Duration Hyprsonic Test Facility at Universiti Tenaga Nasional

This paper describes the development of a short duration hypersonic test facility at the College of Engineering, Universiti Tenaga Nasional (UNITEN). The facility is the first of its kind in Malaysia. The facility will allow various researches to be done in the field of high speed supersonic and hypersonic flows. It is designed so that it can be used as a free piston tunnel, shock tube and shock tunnel. The maximum mach number obtainable depends on the type of the driver and driven gases. It is shown that a mach number of 4 can be achieved if CO2 is used as the driven gas and Helium is used as the driver gas with diaphragm pressure ratio of 74.76. Experimental measurements were performed with the facility working as shock tube. The barrel temperature was measured using in-house developed fast response surface junction E-type thermocouple while the pressure was measured using fast response quartz pressure transducer. The pressure and temperature results clearly show the formation of shock wave and its reflection causing the pressure and temperature to increase rapidly

An introduction to a homogeneous charge compression ignition engine

Homogeneous charge compression ignition (HCCI) engine technology is relatively new and has not matured sufficiently to be commercialised compared with conventional engines. It can use spark ignition or compression ignition engine configurations, capitalizing on the advantages of both: high engine efficiency with low emissions levels. HCCI engines can use a wide range of fuels with low emissions levels. Due to these advantages, HCCI engines are suitable for use in a hybrid engine configuration, where they can reduce the fuel consumption even further. However, HCCI engines have some disadvantages, such as knocking and a low to medium operating load range, which need to be resolved before the engine can be commercialised. Therefore, a comprehensive study has to be performed to understand the behaviour of HCCI engines

MILD Combustion: A Technical Review Towards Open Furnace Combustion

Moderate or Intense Low oxygen Dilution (MILD) combustion is one of the best alternative new technologies for clean and efficient combustion. MILD combustion has been proven to be a promising combustion technology for industrial applications with decreased energy consumption due to the uniformity of temperature distribution, also producing low NO and CO emissions. This article provides a review and discussion of the recent research and development in MILD. Furthermore, the problems and focuses are summarized with some suggestions and therefore presented on upgrading an application of MILD in the future. Currently MILD combustion has been applied in closed furnace. For closed furnace, the preheating supply air is no longer required since the recirculation inside the enclosed furnace will self preheats the supply air and self dilutes the oxygen in the combustion chamber. The possibility of using open furnace MILD combustion was discussed and reviewed

Investigating corrosion effects and heat transfer enhancement in smaller size radiators using CNT-nanofluids

Nanofluids have been extensively studied in the past to enhance the heat transfer performance and efficiency of systems. However, corrosion effects have been paid very little attention and thus this work presents an experimental study on the effect of carbon nanotubes (CNT) on corrosion of three different metals under study such as aluminium alloy, stainless steel and copper, respectively. The work was further extended to study the heat transfer performance in a car radiator of two different sizes. Both the studies were performed using four different fluids such as water, ethylene glycol, 0.02 % CNT-nanofluid and 0.1 % CNT-nanofluid, respectively. It was observed that among the three metals, the highest rate of corrosion occurs to aluminium, followed by stainless steel and copper, irrespective of the fluid used. The rate of corrosion increased with the increase in temperature (27–90 °C) in all cases. The experimental results showed that the stable CNT-nanofluids prepared in this work showed better heat transfer performance in both engines. Moreover, the smaller radiator using the CNT-nanofluids depicted enhanced heat transfer rates compared to the standard radiator using water and ethylene glycol

A systems thinking approach to address sustainability challenges to the energy sector

The energy sector is an intrinsically dynamic and complex system, and therefore its behaviour is not solely controlled by constituent components. Rather, it is a consequence of dynamic interactions among them. To properly manage such a system in a sustainable manner, it is necessary to understand the underlying dynamics of component interactions. Despite this, the interconnections between components of the energy sector in research and policy have received little attention. Here, we outline crucial limitations of previous efforts and emphasize the importance of using systems thinking in addressing the energy sector's sustainability challenges. We demonstrate this by a case study of the Australian energy sector, which has experienced emerging sustainability issues. Research findings show that current policies promoting energy development in the country are likely to be ‘fixes that fail’ that ultimately undermine sustainability. To achieve in building a sustainable energy sector, the policy must focus on implementing long-term solutions and avoid short-term quick fixes

Design of film thickness instrument for fibre polymer composites tribological experiments

New technique to measure film thickness in tribological experiments is presented in the current study. The technique is based on strain gauges circuit fixed on a lever of the block on ring (BOR) machine. Conversion of strain gauge readings was made to determine the film thickness values. For testing purposes, experiments were conducted using the new machine to investigate the wear performance of glass/polyester composites. The tests were performed against aluminium counterface at different applied loads (0.5 N to 3 N) for 10 minutes sliding time under wet contact conditions. From the results, the new technique highly assisted to analyise the tribological results. The SEM showed different damage features

Experimental investigation on combustion behaviour, performance and emission of fusel oil-gasoline blends using turbocharged SI engine

Because of rising energy demand and pollution concerns in the transportation and industrial sectors, alternative fuel development is critical. The fusel oil, which is a by-product of ethanol distillation molasses, is receiving a lot of interest. The combustion characteristics, performance, and emissions of a 1.8L turbocharged four-cylinder, port injection, spark-ignition engine will be used to compare fusel oil blends with gasoline in this study. The experiment was carried out at a constant engine speed of 2000 rpm with a throttle load of 10-40%. Four samples with various ratios of gasoline combined with fusel oil were tested (100% gasoline, 10%, 20%, and 30% are referred to as F0, F10, F20, and F30 respectively). As a result, compared to gasoline, fusel oil blends increase Brake Specific Fuel Consumption (BSFC) by 5-22%. In comparison to gasoline, the combustion behaviour of in-cylinder pressure, Rate of Heat Release (ROHR), Rate Of Pressure Rise (ROPR), and Mass Fraction Burn (MFB) shows an early 2-3 Degree Crank Angle (CAD). Due to differences in attributes and oxygen content, the Brake Thermal Efficiency (BTE) of combustion utilising fusel oil blends suffers a modest drop of 13-16%. When compared to gasoline, fusel oil blends emit 3-4% less hydrocarbon (HC), 7.5-24.5% less carbon monoxide (CO), and 18-36% less nitrogen oxide (NOx). To summarise, fusel oil blends without water extraction blended with gasoline have a substantial impact on turbocharger engine functioning