※一部利用できない機能があります
| 1.
論文 |
論文
|
佐々木, 徹 ; 天野, 俊輔 ; 渡辺, 哲也 ; 世取山, 幸作 ; 古畑, 朋彦 ; 新井, 雅隆
概要:
application/pdf<br />Journal Article<br />A low NO_x combustor for kerosene-fueled micro gas turbine based on a new concept was proposed. The combustor consisted of primary and secondary combustion zones, and they were
…
connected by a throat. A swirler was set between the primary and secondary combustion zones. In order to enhance recirculation of burned gas in the primary combustion zone, combustion air was introduced through the swirler and forced to flow upward to the combustor bottom. In this study, effects of configuration of primary combustion zone on combustion gas flow in it were investigated. The length of primary combustion zone, swirler vane angle, diameter of throat and height of guide vane were changed independently from the standard configuration. Distributions of gas flow in the primary combustion zone were measured with LDA. The relation between combustion stability and the distributions of gas flow was discussed, and it was found that appropriate combustion gas recirculation in the primary combustion zone was necessary to keep combustion stability high.
続きを見る
|
||
| 2.
論文 |
論文
|
荒木, 幹也 ; 新井, 正明 ; 岡本, 光司 ; 石間, 経章 ; 小保方, 富夫
概要:
application/pdf<br />Journal Article<br />Velocity measurement of an intermittent high-speed flow inside a micro wave ro
…
tor cell was carried out by utilizing a laser Doppler anemometry (LDA). The cell is 3×3mm rectangular tube, whose length is 42mm. The pressure ratio and rotor speed of the wave rotor were set at 2.5 and 5000rpm, respectively. Ethanol droplets were seeded into the flow as scattering particles. By use of laser beam expanders, the beam intersection volume of the LDA optics was minimized, and submillimeter spatial resolution is realized while a wide velocity range (-100 to 300m/s) is kept. It is shown that the velocity histories at local positions inside the wave rotor cell can be obtained with the LDA optics. The rapid velocity increase and decrease, due to the primary and secondary shock waves, are observed, and the propagation speed of the primary shock wave was estimated. It is shown that the spatial distribution of the maximum velocity inside the cell is constant, and that the boundary layer thickness inside the cell is smaller than 0.5mm. It is shown that the effect of viscosity is relatively small in such a micro wave rotor.
続きを見る
|
||
| 3.
論文 |
論文
|
野村, 友和 ; 高橋, 易資 ; 武田, 親士 ; 石間, 経章 ; 小保方, 富夫
概要:
application/pdf<br />Journal Article<br />Characteristics of the flow inside an engine cylinder model have been evaluated by a particle image velocimetry (PIV) and a laser Doppler anemometer (LDA). Verifications of the results by Partial
…
Cells in Cartesian coordinate method numerical simulation have been also made by the experiment results. The model engine head that has two intake valves and transparent cylinder are used in the steady state flow condition. The tests are conducted by single- and dual- valve open condition with 8mm valve lift in-1470 Pa suction gauge pressure. The comparisons between the PIV and the LDA experiments show almost the same tendencies for mean velocities and turbulence intensities in the whole experimental regien qualitatively and also quantitatively. The differences in the valve open condition are clearly observed in the integral length and time scales that are estimated from the PIV and LDA data respectively. It is shown that the PIV results are useful for verification of numerical results, which agree reasonably with those of experiments.
続きを見る
|
||
| 4.
論文 |
論文
|
野村, 友和 ; 高橋, 易資 ; 石間, 経章 ; 小保方, 富夫
概要:
application/pdf<br />Journal Article<br />Boundary layer flow over a multi-holed plate is analyzed in this paper. Two perforated plates which have different diameter of holes and a flat plate are tested in the rectangular duct. The
…
diameters of holes are 20mm or 40mm in staggered arrangement and the all plates are 10mm in thickness. These studies are carried out by means of two-dimensional LDA (laser Doppler anemometer) and numerical simulation with Partial Cell method. The mean flow velocity and the relative turbulence intensity are 4.5m/s and 2% respectively in both the experiment and the calculation. Comparisons of flows over the three plates are made for the mean velocity, turbulence intensity and Reynolds stress. In addition, the difference in turbulence flow structure depending on the diameter of holes has been discussed by experimental results.
続きを見る
|
||
| 5.
論文 |
論文
|
野村, 友和 ; 石間, 経章 ; 小保方, 富夫
概要:
application/pdf<br />Journal Article<br />Spatial correlation measurements of velocity fluctuations in turbulent flow over a rectangular cube are presented. Direct measurement of spatial correlation requires simultaneous measurement of
…
velocities at two or multi-points in the flow. Therefore this study is carried out by means of a particle image velocimetry (PIV) or two LDAs (laser Doppler anemometer) composed by He-Ne and Ar^+ lasers. The cube is set on the floor of the wind tunnel. At the inlet, the mean flow velocity and the relative turbulence intensity are 4.0m/s and 1.5%, respectively in both experiments. Under this condition, the flow Reynolds number based on the rectangular cube height and the mean velocity is about 8800. Firstly, comparisons are made for longitudinal and transversal spatial correlation coefficients measured by LDA. Secondly, distributions of integral length scales distributions acquired by LDA and PIV have been discussed. In addition, the validities of integral length scale calculated by Taylor's hypothesis are evaluated in the flow.
続きを見る
|
||
| 6.
論文 |
論文
|
石間, 経章 ; 中村, 晋 ; 助名, 亮一 ; 小保方, 富夫 ; 河内, 勝義 ; 小林, 一光
概要:
application/pdf<br />Journal Article<br />An LDA flow rate meter which is based on the LDA (Laser Doppler anemometer) te
…
chnique has been developed. The principle of the LDA flow rate meter applied for circular pipe is following. The center line velocity of pulsating pipe flow was measured by the LDA. The velocity distribution profile in the pipe cross section can be numerically estimated, and then the instantaneous flow rate was calculated by the integration of the profile. Firstly, it was applied and evaluated at the pulsating flow made by an artificial heat-lung system. The system has a double roller pump with a vinyl tube of Ω-shape. Secondly, an intermittent flow rate at high fuel pressure injection system was also measured. Swirl injector generated the oscillating pipe flow under high line pressure of 5 MPa at injection frequencies of 20 and 40 Hz. There was a little difficulty at the measurement of injection flow depending on the zero velocity shifting. Finally, a correction method of zero shifting was proposed and the applicability of the flow rate meter was demonstrated.
続きを見る
|
||
| 7.
論文 |
論文
|
石間, 経章 ; 助名, 亮一 ; 小保方, 富夫 ; 河内, 勝義 ; 小林, 一光
概要:
application/pdf<br />Journal Article<br />Characteristics of spray injected from the five types of swirl nozzle, which were the same design however differed in the static flow rates as 600, 700, 800, 900 and 1 000 cc/min respectively, have
…
been evaluated by a phase Doppler anemometer (PDA) and a
続きを見る
|
||
| 8.
論文 |
論文
|
高橋, 易資 ; 野村, 友和 ; 石間, 経章 ; 小保方, 富夫
概要:
application/pdf<br />Journal Article<br />The PCC (Partial Cells in Cartesian coordinate) method CFD code featured with
…
less pre-processing time was used in this study to calculate the flow field around a rectangular cube. The turbulence model was consisted using a low Reynolds number κ-ε model and log law. To test the case of existence of many partial cells, the rectangular cube was set with 10 degrees of offset angle to the flow direction, and calculation mesh does not correspond to the cube surface. The mean flow velocity and turbulence intensity were set to 4.0 m/s and 1.5%, respectively in both experiment and calculation. The experiments were carried out by using two-dimensional laser Doppler anemometry (LDA) and particle image velocimetry (PIV). The numerical results were compared with the experimental results. Both results show good agreement between calculation and experiment in the mean velocity, turbulence intensity and Reynolds stress.
続きを見る
|
||
| 9.
論文 |
論文
|
石間, 経章 ; ヨゼフ, イスマイル M ; 小保方, 富夫
概要:
application/pdf<br />Journal Article<br />Particle laden water jet have been analyzed by means of a laser Doppler anemom
…
eter (LDA). Glass spheres of 389μm in mean diameter were loaded into the injection water by a particle mixer and after then injected into still water bath. The particle/water jet injectors were made by brass pipes of which diameters were 5 and 8 mm. The mean velocities of the center of the jet were set as 1.8 and 1.5 m/s for 5 and 8 mm pipes, respectively. The initial volume fraction was set as 0.087% in all experiments. The results of vertical relative velocity between particle and water indicate that the particles have same velocity as water at the outlet of the jet however particle velocities are larger than that of water at the expanded jet in downstream. From the results of the transverse relative velocity, it is considered that the particle can get larger velocity than water at a certain downstream from the outlet. These features are well explained by using local Stokes number defined by local time scale of the turbulence and particle time constant as well as Saffman's lift force.
続きを見る
|
