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

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

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

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

IMECE2009-10160 NEW TECHNIQUE MEASURING FILM THICKNESS FOR TRIBOLOGICAL MACHINES

ABSTRACT In the present work, a prototype machine was developed for film thickness measurement for tribological tests. The configuration of the machine was based Block on Ring (BOR) technique. In the current machine, frictional forces and film thickness were measured using load cell and strain gauges, respectively. Calibration was made to determine the real film thickness. Experiments were conducted using the newly developed machine to investigate the film thickness during sliding of UHMWPE against aluminum alloy counterface. The tests were performed at applied loads (1.47 N -2.94 N). The results revealed that increases the applied load reduces the film thickness which in turn played a main role in controlling the surface characteristics of the polymer

Central composite design adoption for assessing the tio quality using response surface method

Stability is a major issue in every nanolubricant. The UV visible spectrophotometry approach is one method for assessing the dispersion quality standard of a nanolubricant. UV visible spectrophotometry is adopted to determine the absorbance level of a nanolubricant. This method assesses how well a nanolubricant absorbs UV rays emitted by a light source. A central composite design based on surface response was used to assess the influence of concentration and standing time on the absorbance ratio of TiO2-POE nanolubricant. The TiO2-POE sample was synthesized in two steps with a 0.02-0.2 vol% concentration range. A homogenizer was used to ultrasonicate the samples for 80 min. Then, U.V. visible spectrophotometry was used to examine the absorbance ratio of each sample from day 1 to day 15. Sixteen runs were performed to comply with a quadratic design for experimental data collection, then fitted using face canter alpha. The ANOVA analysis revealed that the experimental data fit the polynomial model, with an R2 value of 0.9902 and a model F-value of 201.91. This phenomenon confirms the significance of the model. The Predicted R2 of 0.9038 agrees reasonably with the Adjusted R2 of 0.9853. The findings suggest that the optimum concentration is 0.11 vol%, with an absorbance value of 0.990206 and a desirability level of 1.000

The Tensor-Vector-Scalar theory and its cosmology

Over the last few decades, astronomers and cosmologists have accumulated vast amounts of data clearly demonstrating that our current theories of fundamental particles and of gravity are inadequate to explain the observed discrepancy between the dynamics and the distribution of the visible matter in the Universe. The Modified Newtonian Dynamics (MOND) proposal aims at solving the problem by postulating that Newton's second law of motion is modified for accelerations smaller than ~10^{-10}m/s^2. This simple amendment, has had tremendous success in explaining galactic rotation curves. However, being non-relativistic, it cannot make firm predictions for cosmology. A relativistic theory called Tensor-Vector-Scalar (TeVeS) has been proposed by Bekenstein building on earlier work of Sanders which has a MOND limit for non-relativistic systems. In this article I give a short introduction to TeVeS theory and focus on its predictions for cosmology as well as some non-cosmological studies.Comment: 44 pages, topical review for Classical and Quantum Gravit

Jet- and Wind-Driven Ionized Outflows in the Superbubble and Star-Forming Disk of NGC 3079

HST WFPC2 images are presented that span the inner 19 kpc diameter of the edge-on spiral galaxy NGC 3079; they are combined with ground-based Halpha+[N II] Fabry-Perot spectra and VLA images of radio polarization vectors and rotation measures. Ionized gas filaments within 9 kpc diameter project ~3 kpc above the disk, with the brightest forming the 1 kpc diameter superbubble. They are often resolved into strands ~0."3 (25 pc) wide which emerge from the nuclear CO ring as five distinct gas streams with velocity gradients and dispersions of hundreds of km/s. One stream flows for 250 pc and aligns with the VLBI-scale radio jet, the other four are not connected to the jet, instead curving to the vertical 0.6 kpc above the galaxy disk, then dispersing in a spray of droplets each with ionized mass ~1000 sqrt(f) Msun (volume filling factor f > 0.003 from our data). Shredded clumps of disk gas form a similar structure in hydro models of a galaxy-scale wind. The pattern of magnetic fields and the gas kinematics also suggest a wind of mechanical luminosity 10^43 erg/s that has stagnated in the galaxy disk at radius ~800 pc, flared to larger radii with increasing height as the balancing ISM pressure reduces above the disk, and entrained dense clouds into a vortex. Total KE and momentum of the filaments are (0.4-5)x10^55 sqrt(f) ergs and (1.6-6)x10^47 sqrt(f) dyne s. A star-forming complex elsewhere in the galaxy shows a striking spray of linear filaments that extend for hundreds of parsecs.Comment: Accepted to ApJ, 31 pages, 15 figures (some color). High-fidelity figs at http://www.physics.unc.edu/~cecil/science/n3079.htm