期刊文献+
共找到5篇文章
< 1 >
每页显示 20 50 100
Study of Interaction between Supersonic Flow and Rods Surrounded by Porous Cavity 被引量:1
1
作者 Minoru YAGA Kenji YAMAMOTO +1 位作者 Piotr DOERFFER kenyu oyakawa 《Journal of Thermal Science》 SCIE EI CAS CSCD 2006年第4期324-330,共7页
In this paper, some preliminary calculations and the experiments were performed to figure out the flow field, in which some rods were normally inserted into the main flow surrounded by a porous cavity. As a result, it... In this paper, some preliminary calculations and the experiments were performed to figure out the flow field, in which some rods were normally inserted into the main flow surrounded by a porous cavity. As a result, it is found that the starting shock wave severely interacts with the rods, the bow shock wave, its reflections, and the porous wall, which are numerically well predicted at some conditions. Moreover, inserting the rods makes the pressure on the upper wall in the porous region increase when the main flow in the porous region is completely supersonic. The calculations also suggest that three rods cause the widest suction area. 展开更多
关键词 shock wave compressible flow porous cavity bow shock wave rod
原文传递
Flow Characteristics of Rectangular Underexpanded Impinging Jets 被引量:1
2
作者 Minoru YAGA Yoshio KINJO +1 位作者 Masumi TAMASHIRO kenyu oyakawa 《Journal of Thermal Science》 SCIE EI CAS CSCD 2006年第1期59-64,30,共7页
In this paper, the flow fields of underexpanded impinging jet issued from rectangular nozzles of aspect ratio 1, 3 and 5 are numerically and experimentally studied. Two dimensional temperature and pressure distributio... In this paper, the flow fields of underexpanded impinging jet issued from rectangular nozzles of aspect ratio 1, 3 and 5 are numerically and experimentally studied. Two dimensional temperature and pressure distributions are measured by using infrared camera and the combination of a pressure scanning device and a stepping motor, respectively. The variation of the stagnation pressure on the impinging plate reveals that a hysteretic phenomenon exists during the increasing and decreasing of the pressure ratio for the aspect ratio of 3.0 and 5.0. It is also found that the nozzle of aspect ratio 1.0 caused the largest total pressure loss Pc /p0= 0.27 at the pressure ratio of Po /p0 = 6.5, where Pc is the stagnation center pressure on the wall, P0 the upstream stagnation pressure, Pb the ambient pressure. The other two nozzles showed that the pressure loss Pc / P0 =0.52 and 0.55 were achieved by the nozzles of the aspect ratio 3,0 and 5.0, respectively. The comparison between the calculations and experiments is fairly good, showing the three dimensional streamlines and structures of the shock waves in the jets. However, the hysteresis of the pressure variations observed in the experiments between the pressure ratio of 3.5 and 4.5 cannot be confirmed in the calculations. 展开更多
关键词 compressible flow shock wave under-expanded rectangular impinging jet CFD.
原文传递
Experimental and Numerical Study of Twin Underexpanded Impinging Jets
3
作者 Minoru Yaga Minoru Okano +1 位作者 Masumi Tamashiro kenyu oyakawa 《Journal of Thermal Science》 SCIE EI CAS CSCD 2003年第3期255-259,共5页
In this paper, the dual underexpanded impinging jets are experimentally and numerically studied. The experiments were performed by measuring the unsteady and averaged wall static pressures and by visnalizing density f... In this paper, the dual underexpanded impinging jets are experimentally and numerically studied. The experiments were performed by measuring the unsteady and averaged wall static pressures and by visnalizing density fields using schlieren method. Numerical calculations were also conducted by solving unsteady three dimensional compressible Navier-Stokes equations with Baldwin-Lomax turbulence model. The main parametm''s for the dual jets are the non-dimensional distance between the two nozzle centers H/D covering 1.5, 2.0, the nozzle to plate separation L/D 2.0, 3.0,4.0 and 5.0 and the pressure ratio defined by Po/Pb 1.0-6.0, where D is the diameter of each nozzle exit, Po the stagnation pressure and Pb the back pressure. It is found that the agreement between the experiments and the calculations is good. The fountain flow at the middle of the two jets is observed both in the experiments and the calculation. According to FFT analysis of the experiments for the twin jets,relatively low frequgncy (up to 5 kHz) is dominant for H/D =1.5, L/D =2.0 and pressure rafio po/Pb =3.0 and 5.0,which is confLrmed by the experiments. 展开更多
关键词 可压缩流体力学 冲击波 碰撞射流 CFD 计算流体力学 喷射流动 实验研究 数值分析
原文传递
Synchronal Measurement of Flow Structure and Heat Transfer of Impingement Jet
4
作者 Shoichi MATSUDA Naomichi SAJI +2 位作者 Minoru YAGA Masaaki ISHIKAWA kenyu oyakawa 《Journal of Thermal Science》 SCIE EI CAS CSCD 2010年第3期228-233,共6页
This paper will present the characteristics of flow behavior and thermal field of both free and impingement jet issued from a circular orifice nozzle at Re=8900.The flow behavior of a single round jet and impingement ... This paper will present the characteristics of flow behavior and thermal field of both free and impingement jet issued from a circular orifice nozzle at Re=8900.The flow behavior of a single round jet and impingement jet was observed by smoke flow visualization recorded by a high speed camera using 5000 frame per second.Heat transfer coefficient on the impingement surface was measured by means of infrared camera (TVS-8500,Avio) with a two-dimensional array of Indeum-Antimony (In Sb) sensors varying in the separation distance between the nozzle and the target plate.The heat transfer coefficient changes in time and spatial.Therefore,the root mean square distribution of the heat transfer was obtained from the data.As a result,it was confirmed that the longitudinal vortex was observed outside of the ring vortex,and then the longitudinal vortex was penetrated in the jet flow.Moreover,the high value of root mean square of the heat transfer coefficient has spread radially in stripy manner,which is caused as the results of the longitudinal vortexes flowing in the radial direction on the impingement plate. 展开更多
关键词 Impingement jet Forced convection Heat transfer Ring vortex Longitudinal vortex
原文传递
Fluid Flow and Infrared Image Analyses on Endwall Fitted with Short Rectangular Plate Fin
5
作者 kenyu oyakawa Islam Md. DIDARUL Minoru YAGA 《Journal of Thermal Science》 SCIE EI CAS CSCD 2006年第2期145-151,共7页
An experimental investigation is carded out to study fluid flow and heat transfer characteristics on the endwall fitted with arrays ( 7 × 7 ) of short rectangular plate fins of different pattern (co-angular an... An experimental investigation is carded out to study fluid flow and heat transfer characteristics on the endwall fitted with arrays ( 7 × 7 ) of short rectangular plate fins of different pattern (co-angular and zigzag) for different pitch ratio. Experiments were conducted in a rectangular duct of 50 mm height for an air flow of Reynolds number ranged from 18750 to 62500 based on the equivalent diameter and air velocity of the duct. Infrared image analysis technique was employed to make clear the characteristics of local heat transfer coefficients on fin base, endwall and overall surface. Flow pattern around the short rectangular plates were visualized by inducing fluorescent dye in a water channel and longitudinal vortices were observed. Increasing the distance between plates in flow direction causes heat transfer enhancement for co-angular pattern, while decreasing the distance causes heat transfer enhancement for zigzag pattern. Zigzag pattern with pitch ratio 2 is found to be more effective in heat transfer enhancement than any other cases investigated. 展开更多
关键词 infrared image rectangular plate convection heat transfer flow visualization
原文传递
上一页 1 下一页 到第
使用帮助 返回顶部