Investigation of the turbulence characteristics in the swirling flow of a gun-type gas burner with two different hot-wire probes

Jang-Kweon Kim 대한기계학회 2008 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.22 No.1

Mean velocities and turbulence characteristics in the swirling flow of a gun-type gas burner (GTGB) were measured with a triaxial hot-wire probe (T-probe) and compared with previous data measured with an X-type hot-wire probe (Xprobe). Vectors and axial mean velocity data obtained by the measurement of the two types of probes in the horizontal plane and in the cross section differ in magnitude, but have very similar shape in overall distribution. Axial mean velocity components show especially wide differences around the slits and outer part of the swirl vanes within the range of X/R=2. Also, various turbulence intensities appear in a similar trend to axial mean velocity components within the range of X/R=2. The radial component of turbulence intensity around the slits and the outer part of swirl vanes above the range of X/R=2 has an opposite phenomenon. On the whole, the T-probe’s measurements appear smaller than the X-probe’s. This shows that the X-probe is better than the T-probe, especially on the swirling flow because it is much easier to use.

실험을 통한 풍력발전기의 후류구조 분석

박지웅(Park, Ji-Woong),김호건(Kim, Ho-Geon),신형기(Shin, Hyung-Ki),이수갑(Lee, Soo-Gab) 한국신재생에너지학회 2006 한국신재생에너지학회 학술대회논문집 Vol.2006 No.06

To generate electricity from wind energy, wind turbine generally has a rotor blade. Since this rotor blade is a kind of the rotating machinery, the wake from the rotor is very Important role in the side of the aerodynamic performances. Thus the study about wake is essential to analyze wind turbine aerodynamics. In this study wake characteristics are analyzed by hot-wire probe in the K.A.F.A(Korea Air Force Academy) wind tunnel. It is possible to analyze the wake characteristics by hot-wire probe from acquiring the velocity fluctuations at given positions in the flow. This velocity data are arranged by trigger signal at same azimuth of the blade in periodic manner of the rotor blade. From this various wake characteristics are found : radial and axial position of the tip vortex, vortex core characteristics in the flow etc.

Gun식 가스버너의 연소실내 난류 선회유동장 고찰

김장권(Jang Kweon Kim) 대한기계학회 2009 大韓機械學會論文集B Vol.33 No.9

The turbulent swirling flow field characteristics of a gun-type gas burner with a combustion chamber were investigated under the cold flow condition. The velocities and turbulent quantities were measured by hot-wire anemometer system with an X-type probe. The turbulent swirling flow field in the edge of a jet seems to cause a recirculation flow from downstream to upstream due to the unbalance of static pressure between a main jet flow and a chamber wall. Moreover, because the recirculation flow seems to expand the main jet flow to the radial and to shorten it to the axial, the turbulent swirling flow field with a chamber increases a radial momentum but decreases an axial as compared with the case without a chamber from the range of about X/R=1.5. As a result, these phenomena can be seen through all mean velocities, turbulent kinetic energy and turbulent shear stresses. All physical quantities obtained around the slits, however, show the similar magnitude and profiles as the case without a chamber within the range of about X/R=1.0.

Gun식 가스버너의 난류 선회유동장에 미치는 덕트의 영향

김장권(J. K. Kim),오석형(S. H. Oh) 한국동력기계공학회 2009 한국동력기계공학회 학술대회 논문집 Vol.2009 No.6

The turbulent flow field characteristics of a gun-type gas burner with and without a duct were investigated under the isothermal condition of non-combustion. Vectors and mean velocities were measured by hot-wire anemometer system with an X-type hot-wire probe in this paper. The turbulent flow field with a duct seems to cause a counter-clockwise recirculation flow from downstream to upstream due to the unbalance of static pressure between a main jet flow and a duct wall. Moreover, the recirculation flow seems to expand the main jet flow to the radial and to shorten it to the axial. Therefore, the turbulent flow field with a duct increases a radial momentum but decreases a axial momentum. As a result, an axial mean velocity component with a duct above the downstream range of about X/R=1.5 forms a smaller magnitude than that without a duct in the inner part of a burner, but it shows the opposite trend in the outer part.

열선유속계를 이용한 좁은 유로 내 유속 측정법

김원갑(Won-Kap Kim),한성호(Seong-Ho Han),최영돈(Young-Don Choi) 대한설비공학회 2007 설비공학 논문집 Vol.19 No.2

It was noted by the several researchers that the voltage outputs in response to a single yawed hot-wire sensor in a flow perpendicular to the axis deviate from the theoretical voltage output by King's law and Jorgensen's relation. This study noticed that the calibration coefficients of original Grande's method are not constant and fairly sensitive to the radial angle (α<SUB>R</SUB>). For more accuracy, this study interpolated the parameters of the Grande relation as a function of radial angle and compared velocity components with ones by Jorgensen and original Grande relation in the calibration jet flow. Finally, as a test case, 3-dimensional turbulent flows of the inlet plane of 180 degree bend are measured and compared the velocity components by above three methods and showed the characteristics of the flows.

Experimental Investigation on the Turbulence Augmentation of a Gun-type Gas Burner by Slits and Swirl Vanes

Kim, Jang-kweon The Korean Society of Mechanical Engineers 2004 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.18 No.10

The purpose of this paper is to investigate the effects of slits and swirl vanes on the turbulence augmentation in the flow fields of a gun-type gas burner using an X-type hot-wire probe. The gun-type gas burner adopted in this study is composed of eight slits and swirl vanes located on the surface of an inclined baffle plate. Experiment was carried out at a flow rate of 450 ι/min in burner model installed in the test section of subsonic wind tunnel. Swirl vanes playa role diffusing main flow more remarkably toward the radial direction than axial one, but slits show a reverse feature. Consequently, both slits and swirl vanes remarkably increase turbulence intensity in the whole range of a gun-type gas burner with a cone-type baffle plate.

Investigation of the Three-Dimensional Turbulent Flow Fields of the Gas Swirl Burner with a Cone Type Baffle Plate(II)

Kim, Jang-kweon The Korean Society of Mechanical Engineers 2001 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.15 No.7

This paper presents three-dimensional mean velocities, turbulent intensities and Reynolds shear stresses measured in the Y-Z plane of the gas swirl burner with a cone type baffle plate by using an X-type hot-wire probe. This experiments is carried out at the flow rate of 450ℓ/min which is equivalent to the combustion air flow rate necessary to heat release 15,000 kcal/hr in a gas furnace. Mean velocities and turbulent intensities etc. show that their maximum values exist around the narrow slits situated radially on the edge of and in front of a burner. According to downstream regions, they have a peculiar shape like a starfish because the flows going out of the narrow slits and the swirl vanes of an inclined baffle plate diffuse and develop into inward and outward of a burner. The rotational flow due to the inclined flow velocity going out of swirl vanes of a cone type baffle plate seems to decrease the magnitudes of mean velocities V and W respectively by about 30% smaller than those of mean velocity U. The turbulent intensities have large values of 50%∼210% within the range of 0.5<r/R<1 and around the narrow slits in front of a burner because the large transverse slope of axial mean velocity remains in these region. Therefore, the combustion reaction is expected to occur actively near these regions. Moreover, the Reynolds shear stresses are largely distributed near the narrow slits of a burner.

Design and Experimental Studies of Radial-Outflow Type Diagonal Flow Fan

Kinoue, Yoichi,Shiomi, Norimasa,Setoguchi, Toshiaki Korean Society for Fluid machinery 2013 International journal of fluid machinery and syste Vol.6 No.1

In order to apply the design method of diagonal flow fan based on axial flow design to the design of radial-outflow type diagonal flow fan which has lower specific speed of 600-700 [$min^{-1}$, $m^3/min$, m], radial-outflow type diagonal flow fan which specific speed was 670 [$min^{-1}$, $m^3/min$, m] was designed by a quasi three-dimensional design method. Experimental investigations were conducted by fan characteristics test, flow surveys by a five-hole probe and a hot wire probe. Fan characteristics test agreed well with the design values. In the flow survey at rotor outlet, the characteristic region was observed. Two flow phenomena are considered as the cause of the characteristic region, one is tip leakage vortex near rotor tip and another is pressure surface separation on the rotor blade.

Design and Experimental Studies of Radial-Outflow Type Diagonal Flow Fan

Yoichi Kinoue,Norimasa Shiomi,Toshiaki Setoguchi 한국유체기계학회 2013 International journal of fluid machinery and syste Vol.6 No.1

In order to apply the design method of diagonal flow fan based on axial flow design to the design of radial-outflow type diagonal flow fan which has lower specific speed of 600-700 [min-1, m3/min, m], radial-outflow type diagonal flow fan which specific speed was 670 [min-1, m3/min, m] was designed by a quasi three-dimensional design method. Experimental investigations were conducted by fan characteristics test, flow surveys by a five-hole probe and a hot wire probe. Fan characteristics test agreed well with the design values. In the flow survey at rotor outlet, the characteristic region was observed. Two flow phenomena are considered as the cause of the characteristic region, one is tip leakage vortex near rotor tip and another is pressure surface separation on the rotor blade.

벽면의 형상 변화에 의한 난류 드래그 관련 Pocket Length Scale 저감연구

유성출,조장현 한국기계기술학회 2019 한국기계기술학회지 Vol.21 No.6

The flow-surface interaction and resulting pockets is the case of a turbulence boundary layer. Conditionally sampled hot-wire measurements within the wall region show that a strong vortex forms within the pocket, bordering the upstream portion, which stay in the wall region. This vortex is the result of the rearrangement of existing sublayer vorticity and its amplification. The work in this area has been applied to the prediction and reduction of drag. The study is focused on determining change in the length scale of the pockets. An important relationship between pocket and modified wall has been found. By changing the upstream boundary condition at the wall, the length scale of pockets were decreased.