Download or read book Atomization and Mixing Performance of Swirl venturi Lean Direct Injection written by Matthew W. Burkhalter and published by . This book was released on 2014 with total page 62 pages. Available in PDF, EPUB and Kindle. Book excerpt: This paper investigated the effects of swirl number and momentum ratio on the atomization and mixing performance of Swirl-Venturi Lean Direct Injection technology. Mie scattering of liquid water, was used to identify the location of water droplets in a cross section of the injector spray. Experiments were performed with three air swirlers with vane angles of 45, 52 and 60 degrees. The swirl number varied from 0.58 to 1.0 and air-to-liquid ratios from 15.8 to 35.6. A transition was observed in the liquid spray distribution for the 52 degree case, which unexpectedly produced twice as much signal than the 45 and 60 degree cases. The main cause of this increased signal may be due to instabilities in the flow when transitioning from low to high swirl states. The results from investigation of swirl number it was found that the spray pattern for is sensitive to swirl intensity. Two flow states were observed for a lower and higher swirl flow as well as a transition state that occurred with the lower swirl state. This work may aid in the specific inquiry of physical mechanisms relating to the effect of flow states on spray distribution. It is found that improved atomization and mixing performance are a result of increase in swirl number.

Download or read book Studies on the Mixing of Liquid Jets and Pre atomized Sprays in Confined Swirling Air Flows for Lean Direct Injection Combustion written by Jun-Young Huh and published by . This book was released on 1998 with total page 350 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Numerical Analysis of Non reacting Flow in a Multi nozzle Swirl Stabilized Lean Direct Injection Combustor written by Ritangshu Giri and published by . This book was released on 2015 with total page 156 pages. Available in PDF, EPUB and Kindle. Book excerpt: A multipoint lean direct injection (MLDI) concept was introduced recently in non-premixed combustion to obtain both low NOx emissions and good combustion stability. In this concept a key feature is the injection of finely atomized fuel into high swirling airflow at the combustor dome that provides a homogenous, lean fuel-air mixture. In order to achieve fine atomization and mixing of fuel and air quickly and uniformly, a well designed swirler system is imperative. The present study aims to investigate non-reacting aerodynamic flow characteristics in one such swirl stabilized multiple lean direct injection (MLDI) nozzle system, using the capabilities of computational fluid dynamics (CFD). The fuel nozzles were designed and provided by United Technologies Aerospace Systems (UTAS). The commercial CFD solver Fluent (Ansys Inc, USA) is incorporated to solve the 3-D Navier-Stokes equations for different CFD numerical formulations and, hence simulate the turbulent swirling flowfield generally associated with such systems. Two separate studies were conducted. The first study analyzed the effect of swirl on a turbulent flowfield in a rectangular chamber with sudden expansion, where the complex nozzle system housing air swirlers and a fuel injector were replaced by simple cylindrical inlets. The second study investigated typical aerodynamic flow features associated with the actual system. The domain for conducting simulations were the entire geometry in both cases. First a trusted grid is developed by carrying out grid refinement analysis for both studies. Then a comparison of different Reynolds-Averaged Navier Stokes (RANS) turbulence model were carried out for both cases. The time averaged Particle Image Velocimetry (PIV) data was used as a basis of comparison and the model most closely matching those values was finalized for further numerical computations. Steady state was employed for both set of problems. For the first problem, different swirl intensities were incorporated at the cylindrical inlet to study the changing structure of flowfield. The second numerical analysis of the actual geometric model was further subdivided into two sections. The first section studied the flowfield changes in this complex model by incorporating different mass flow rates for the same nozzle spacing of S = 1.36d. The solution captures the essential flow features generally associated with a non-reacting swirling flowfield in a LDI combustor. The second section analyzed the change in flowfield structure when the spacing between nozzles were varied from 1.1d to 2.72d. A single nozzle case was also used as a basis for comparison. The results obtained were also compared to the available time averaged PIV data. The effect of inter-nozzle spacing result in flows, where the nozzles interact strongly to a case where nozzles do not interact atleast for most of the axial locations. Thus the results provide a useable CFD model for evaluation of this flowfield while highlighting their areas of uncertainty. In addition to that, they also provide useful prerequisites for conducting further reacting flow analysis for this particular design.

Download or read book Annual Research Briefs written by Center for Turbulence Research (U.S.) and published by . This book was released on 2007 with total page 428 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Fuel air Mixing and Combustion in Swirl Direct Injection Diesel Engines written by A. Y. O. Barrishi and published by . This book was released on 1990 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Theory and Practice of Swirl Atomizers written by Yuriy I Khavkin and published by CRC Press. This book was released on 2003-10-28 with total page 490 pages. Available in PDF, EPUB and Kindle. Book excerpt: In this book, prominent Russian scientist Yuriy I. Khavkin shows that the droplet sizes in swirl atomizers depend only on the specific energy of the liquid drops and on viscosity. The new theory based only on two parameters is shown to be far simpler and in better agreement with experimental data than any previous presentations. The following topics are included in the book: · The solution of the Navier-Stokes equation for a liquid rotating flow · Atomizers for gas turbine combustion chambers · Atomizers for high capacity steam boilers · Atomizers for liquid-propellant rocket engines · Quality of liquid atomization by non-swirl atomizers · A unique table of experimental data of 232 atomizers, enables the reader to find an atomizer with the flow rate from 5 kg/h to 15,000 kg/h Readers will also learn: · To create an atomizer with the given mean droplet size · To create an atomizer with the given droplet size distribution · To create an atomizer with the given limits of flow rate control. The book is intended for the design engineer, as well as the theoretical scientist.

Download or read book ASME Technical Papers written by and published by . This book was released on 2000 with total page 488 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Paper written by and published by . This book was released on 2000 with total page 490 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Coarse Grained Simulation and Turbulent Mixing written by Fenando F. Grinstein and published by Cambridge University Press. This book was released on 2016-06-30 with total page 481 pages. Available in PDF, EPUB and Kindle. Book excerpt: Reviews our current understanding of the subject. For graduate students and researchers in computational fluid dynamics and turbulence.

Download or read book Liquid Fuel Atomization and Mixing in a High Velocity Air Stream written by H. Eickhoff and published by . This book was released on 1984 with total page 8 pages. Available in PDF, EPUB and Kindle. Book excerpt: With respect to the reduction of emissions in combustion processes it is of recent interest to examine the atomization and mixing performance of different types of injection devices for liquid fuel. The present investigation concentrates on air blast atomizers of the plain jet and prefilming type. Measurements of the initial droplet size distribution and final mixing in a duct are presented and discussed. (Author).

Download or read book Mixing of Axially injected Liquid Jets and Pre atomized Sprays in a Lean direct injection LDI Mode written by Jun-Young Huh and published by . This book was released on 1998 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Atomization Performance Predictions of Gas Centered Swirl Coaxial Injectors written by and published by . This book was released on 2007 with total page 10 pages. Available in PDF, EPUB and Kindle. Book excerpt: The ability to predict injector performance can reduce the cost of rocket engine development. This paper details a new theory to predict the atomization efficiency and droplet diameter from the atomization of wall-bounded films with strong gas-phase influences. In this theory atomization occurs when a disturbance is created on the film surface then breaks down into droplets via stripping. The theory relates the mass of film lost via atomization to the mass of liquid introduced into the atomizer to predict atomization efficiency and offers some estimations of primary droplet diameter. A specific example involving a gas-centered swirl coaxial injector is discussed. The results of experiments and simulations are used to support assumptions and are successfully compared to some simple predictions from the theory. Despite the application to a specific injector efforts are made to keep the theory as general as possible so that it applies to many types of injectors and a wide range of operating conditions.

Download or read book High presure Performance of Combustor Segments Utilizing Pressure atomizing Fuel Nozzles and Air Swirlers for Primary zone Mixing written by Robert D. Ingebo and published by . This book was released on 1971 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Influence of Injector Geometry on Fuel air Mixing and Combustion Performance of a Model Combustor written by Leonel Arellano-Ochoa and published by . This book was released on 2000 with total page 308 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book 34th AIAA ASME SAE ASEE Joint Propulsion Conference Exhibit written by and published by . This book was released on 1998 with total page 662 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Investigation of Atomization Mechanisms and Flame Structure of a Twin fluid Injector for Different Liquid Fuels written by Lulin Jiang and published by . This book was released on 2014 with total page 207 pages. Available in PDF, EPUB and Kindle. Book excerpt: Diminishing fossil fuel resources, ever-increasing energy cost, and the mounting concerns for environmental emissions have precipitated worldwide research on alternative fuels. Biodiesel, a popular renewable energy source, is produced from the transesterification process of source oils such as vegetable oil (VO) requiring processing cost and energy input. However, highly viscous glycerol produced as the waste byproduct also decreases the economically viability of biodiesel. Previous studies show that without fuel preheating or hardware modification, high viscosity fuels such as VO and glycerol cannot be burnt cleanly with the application of the typical air blast (AB) injector due to the high viscosity. However, extremely low emissions of diesel, kerosene, biodiesel, straight VO and glycerol flames at the combustor exit are reported using a novel flow blurring (FB) injector. The PDPA measurements in the FB sprays at least 1.0 cm downstream of the injector exit quantitatively show the superior fuel-flexibility and atomization capability of the FB injector as compared to the AB atomizer. This study seeks to gain insight into the detailed flame structure of both conventional and alternative fuels atomized by the FB injector. The atomization mechanism in the FB injector near field is also investigated using a high speed imaging technique and particle image velocimetry (PIV) to explore the FB spray characteristics in the near field of the injector. First, the combustion of diesel, biodiesel and straight vegetable oil (VO) using a Flow Blurring (FB) injector is investigated. Measurements of gas temperature and CO and NOx concentrations at various axial and radial locations of the combustor are acquired using custom-designed thermocouple and gas sampling probes. Heat loss rate through the combustor is estimated from wall temperatures measured by an infra-red camera. A simple droplet model is used to predict fuel vaporization behaviour in the dark-region near the injector exit. Results show that the FB injector produced low-emission clean blue flames indicating mainly premixed combustion for all three fuels. Matching profiles of heat loss rate and product gas temperature show that the combustion efficiency is fuel independent. Next, a fuel-flexible dual-fuel combustor to simultaneously burn methane and/or straight glycerol without preheating either glycerol or air is investigated by utilizing a FB liquid fuel injector. Product gas temperature, NOX and CO emissions at multiple locations inside the combustor are measured to quantitatively assess the flame structure, related to liquid atomization, droplet evaporation, and fuel-air mixing in the near field. The impact of fuel mix and air to liquid mass ratio (ALR) on combustion performance is investigated. Pure glycerol flame is also investigated to demonstrate the fuel flexibility and ease of switching between gas and liquid fuels in the present system. Results show that the methane combustion can assist glycerol vaporization to results in its rapid oxidation. In spite of the differences in the flame structure, profiles of product gas temperature and emissions at the combustor exit reveal that complete and mainly lean premixed combustion with low emissions is achieved for all of the test cases indicating excellent fuel flexibility of the present combustor using the FB injector. Next, high-speed visualization and time-resolved Particle Image Velocimetry (PIV) techniques are employed to investigate the FB spray in the near field of the injector to delineate the underlying mechanisms of atomization. Experiments are performed using water as the liquid and air as the atomizing gas. Flow visualization at the injector exit focused on field of view with the dimension of 2.3 mm x 1.4 mm, spatial resolution of 7.16 æm per pixel, exposure time of 1 æs, and image acquisition rate of 100 k frames per second (fps). Image sequence illustrates mostly fine droplets indicating that primary breakup by FB atomization occurs within the injector. Few larger droplets appearing at the injector periphery undergo secondary breakup by Rayleigh-Taylor instabilities. Time-resolved PIV technique is applied to quantify the droplet dynamics in the injector near field. Plots of instantaneous, mean, and root-mean-square droplet velocities are presented to reveal the secondary breakup process. Results show that the secondary atomization process to produce fine and stable spray is complete within a short distance of about 5.0 mm from the injector exit. These superior characteristics of the FB injector are desirable to achieve clean combustion of different fuels in practical systems. The impact of ALR shows that the increase in ALR improves both primary FB atomization and secondary atomization in the near field. Next, glycerol atomization in the near field of the FB injector is investigated in detail. Time-resolved PIV with exposure time of 1 ms and laser pulse rate of 15 kHz is utilized to probe the glycerol spray at spatial resolution of 16.83 æm per pixel. PIV results describe the droplet dynamics in terms of the instantaneous, mean, and root-mean-square (RMS) velocities, and space-time analysis and probability distribution profiles of the axial velocity. In addition, high-speed imaging (75 kHz) coupled with backside lighting is applied to reveal the glycerol breakup process at spatial resolution of 7.16 æm per pixel and exposure time of 1 æs. Results show that the primary breakup by FB atomization or bubble explosion within the injector results in a combination of slow-moving streaks and fast-moving droplets at the injector exit. Then, the secondary breakup by Rayleigh-Taylor instability occurs at farther downstream locations where the high-velocity atomizing air stretches the streaks into thin streaks that disintegrate into smaller streaks, and subsequently, into fine droplets. Thus, within a short distance downstream of the injector exit (

Download or read book Importance of Axial Swirl Vane Location on Combustion Dynamics for Lean Pre mix Fuel Injectors written by Douglas L. Straub and published by . This book was released on 1998 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: