Download or read book An Experimental Study of Swirling Jets with Different Initial Swirl Profiles written by R. T. Gilchrist and published by . This book was released on 2003 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book An Experimental Study of Swirling Jets written by Ing Kiet Francis Toh and published by . This book was released on 2010 with total page 247 pages. Available in PDF, EPUB and Kindle. Book excerpt: The mean flow properties and the instantaneous flow structures of the jets are then investigated. The introduction and increase of swirl result in a higher jet growth, decay and turbulent intensity, the formation of an off-axis axial velocity maximum and the occurrence of vortex breakdown. The swirl-induced jet growth enhancement can be categorized into three regimes: a low swirl regime in which there is a limited enhancement, a moderate swirl regime in which the enhancement scales with swirl, and a high swirl regime in which vortex breakdown dominates the process. The jet growth behavior in the high swirl regime is found to be dependent on the structure of the jet and the vortex breakdown configuration. A significant change in the flow structures and certain mean flow properties including the centerline and local maximum axial velocity decay are observed in the low and the moderate swirl regimes. These properties appear to be less sensitive to swirl in the high swirl regime after the occurrence of vortex breakdown. The effects of Reynolds number on swirling jets may not be identical to that on a non-swirling jet. The statistical characteristics measured show that low velocity occasions in the vicinity of the jet centerline start to appear at a sufficiently high degree of swirl. These occasions increase with swirl until the eventual occurrence of vortex breakdown. The statistical characteristics of jets that have undergone vortex breakdown are very similar, as they are dominated by the vortex breakdown phenomenon. The mean flow and the statistical measurements also reveal the presence of an unstable vortex breakdown that is difficult to detect using flow visualization and instantanous velocity field measurements.
Download or read book A Numerical and Experimental Study of Confined Swirling Jets written by M. Nikjooy and published by . This book was released on 1989 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Integrated Computational experimental Study of Turbulence Modification and Mixing Enhancement in Swirling Jets written by Jonathan Wayne Naughton and published by . This book was released on 2009 with total page 30 pages. Available in PDF, EPUB and Kindle. Book excerpt: Swirling jet flows have been studied experimentally and computationally and the results have been compared with theory. Three-component Laser Doppler Anemometry (LDA) measurements have been carried out for swirling jets of various strengths and swirl distributions. Radial profiles of velocity have been obtained from the jet exit to 50 diameters downstream. The experimental results are consistent with previous results and with similarity theory for weakly swirling turbulent jets. However, the parametric range and spatial domain of the current data set makes it suitable for validation. Computational simulations have also been performed using a combination of Reynolds Averaged Navier-Stokes (RANS) and Large Eddy Simulation (LES) approaches. The results have been validated with experimental data and used to explore the mechanisms behind the increased mixing enhancement observed. The combined experimental/computational effort is still ongoing, but the experiences to date have demonstrated the effectiveness of such an approach.
Download or read book An Experimental Study of the Velocity Distribution in an Enclosed Swirling Jet written by Sarah Elizabeth Bingman and published by . This book was released on 1983 with total page 134 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Experimental Investigation of Turbulent Swirling Jets written by Sara Toutiaei and published by . This book was released on 2014 with total page 52 pages. Available in PDF, EPUB and Kindle. Book excerpt: In this study, velocity distributions of a swirling and a non-swirling jet flows were obtained using Laser Doppler Anemometer (LDA) in the near field where both jets are at the same stages of development. The resulting mean velocity and Reynolds stress distributions and the energy budgets of the axial Reynolds stresses are assessed. All Reynolds stresses showed higher magnitude in the swirling case compared to the non-swirling one at the same measurement axial locations. The swirling jet is found to exhibit larger production, mean convection and turbulence transport terms in the energy budget of axial Reynolds stress. The result shows faster development of the swirling jet compared with the non-swirling jet and is in consistency with previous studies. The turbulent transport term is found to be responsible for the faster development of the turbulence in the swirling jet.
Download or read book Experimental Study of Combustion and Scalar Mixing in Swirling Jet Flows written by Viacheslav Stetsyuk and published by . This book was released on 2013 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Experimental Study of Regions of Flow Recirculation in Underexpanded Supersonic Swirling Jets written by Jorge Arturo Ahumada Lazo and published by . This book was released on 2018 with total page 272 pages. Available in PDF, EPUB and Kindle. Book excerpt: Flame-holding is accounted as one of the major challenges in scramjet engines. To increase residence time scales, flow recirculation is commonly introduced in the combustors by means of engine wall cavities or bluff-bodies. Either configuration involves the interaction of solid structures with high temperature gases, resulting in elevated heat transfer loads to the engine components. This study investigates the recirculation in supersonic jets caused by swirl as a flame-holding mechanism independent of solid structures. Swirl is imparted to the flow by tangential injection into a convergent nozzle, and a geometrical swirl number Sg is calculated to assess the swirling strength. Schlieren imaging and planar laser Mie scattering (PLMS) techniques are used to evaluate the shock cell structure, and planar particle image velocimetry (PIV) is implemented to characterize the regions of reversal flow. It is found that viscous effects inside the nozzle due to tangential injection become significant in reduced exit diameters and inhibit the formation of vortical recirculating structures. The configuration of inlets used for injection rather than geometrical swirl number alone proves to be deterministic for the onset of recirculation. In certain experimental configurations, Schlieren imaging reveals the existence of recirculating regions. A stagnation point results from impingement of the jet main stream and recirculation and acts as a standing body. It is suggested that a bow shock wave forms about this point. Mie scattering imaging proves entrainment of humidity from the jet shear layer in the form of particles that allow for PIV to be implemented. Jets with reversal are unstable and switch between reversing and non-reversing modes, recirculation structures also fluctuate in the radial and axial directions and even migrate downstream of the Mach disk. This induces further instability in the flow as the pressure distribution is unsteady. PIV analysis allows to obtain characteristic length and time scales based on the radius of recirculation and the characteristic reversal axial velocity. The time scales of the mode-switching phenomenon are evaluated by acquiring Schlieren images at a high frame rate. The non-recirculating mode is significantly suppressed by a moderate addition of axial flow.
Download or read book An Experimental Study of Swirling Flows as Applied to Annular Combustors written by and published by . This book was released on 1997 with total page 296 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Experimental Study of Turbulent Swirling Flows written by Bach Thien Vu and published by . This book was released on 1983 with total page 464 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Experimental Investigation of the Structure of Turbulent Swirling Jets written by Eric J. DeMillard and published by . This book was released on 2019 with total page 56 pages. Available in PDF, EPUB and Kindle. Book excerpt: Experimental investigations were carried out in both non-swirling and swirling jets at a Re = 105. A stereoscopic particle image velocimetry (SPIV) system was used to acquire the measurements in both axial-radial and radial-tangential planes at x/D = (1-10). Multiple test cases were taken where both the swirl magnitude and swirl distribution was adjusted. Proper Orthogonal Decomposition (POD) was then applied to the measurements to characterize turbulence structure. The results indicate that swirl causes the structure to be more ordered and shifts the relative amount of energy from axisymmetric structure to azimuthal structure.
Download or read book Experimental Study of Incompressible Jets with Different Initial Swirl Distribution written by Robert Treat Gilchrist and published by . This book was released on 2005 with total page 196 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book An Experimental and Numerical Study of Surface Interactions in Turbulent Swirling Jets written by Zahir Uddin Ahmed and published by . This book was released on 2016 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Experimental Investigation of Swirling Jet Flow written by X. Hong-ging and published by . This book was released on 1982 with total page 14 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Experimental Study of Passive Scalar Mixing in Swirling Jet Flows written by Ramis Örlü and published by . This book was released on 2006 with total page 111 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Experimental and Theoretical Study of Turbulent Swirling Jets Issuing from a Round Orifice written by Nehemiah A. Chigier and published by . This book was released on 1965 with total page 76 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Experimental and Numerical Studies of Turbulent Swirling Jets in Ducted Streams written by and published by . This book was released on 1975 with total page 762 pages. Available in PDF, EPUB and Kindle. Book excerpt:
