共查询到17条相似文献,搜索用时 140 毫秒
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旁通型喷嘴喷射器的环隙结构对性能的影响 总被引:1,自引:0,他引:1
《工程热物理学报》2015,(11)
对一种新型带旁通喷嘴的喷射器的性能进行了实验研究,分析了旁通喷嘴结构对喷射器引射特性的影响规律,结果表明:当喷射器处于临界模式下,旁通型喷嘴喷射器的引射性能要优于常规喷射器。环隙空腔间隙和第二喉部直径对引射性能的影响是非线性的。当环隙空腔间隙较小时,引射性能随着第二喉部直径的增大而提高;增大环隙空腔间隙后最优第二喉部直径将会减小。 相似文献
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针对CO2吸收式制冷系统存在吸收效率低、膨胀损失大的问题,选择使用一种带有喷射器的新型CO2喷射器吸收式制冷系统。通过模型计算研究了工作流体及引射流体的质量流量与压力对喷嘴临界截面直径和圆柱形混合室截面直径的影响。结果表明,当其他条件固定不变时,喷嘴临界截面直径Db随工作流体质量流量在0.02~0.10kg/s范围内增加时从6.2mm增加到12.3mm,随工作流体压力在0.1~0.4MPa范围内增加时从66mm减小到34mm;圆柱形混合室截面直径De随引射流体质量流量在0.02~0.10kg/s范围内增加时从63mm增加到91mm,随引射流体压力在0.0023~0.0073MPa范围内增加时从37mm增加到83mm,由此可知圆柱形混合室截面直径存在最佳值。 相似文献
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《工程热物理学报》2020,(7)
根据脉冲流体的动量方程,推导出了用于负压钻井液振动筛的脉冲气液喷射器的基本性能方程,从其工程实际情况出发对该基本性能方程进行简化,得到了脉冲气液喷射器的喷射系数与重要参数之间的关系式。运用MATLAB软件对性能方程编程后进行理论求解,得出了不同参数下脉冲气液喷射器的理论时均性能曲线。最终运用Fluent软件对脉冲气液喷射器进行了三维模拟,得出了结构参数和工作参数对其喷射性能的影响曲线。将两种软件得到的性能曲线进行对比,发现曲线趋势相近,验证了脉冲负压钻井液振动筛中脉冲气液喷射器的性能方程和数值模拟的有效性。研究结果为负压钻井液振动筛中脉冲气液喷射器的设计提供了理论指导依据。 相似文献
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The present study deals with the visualization of the air flow inside a supersonic ejector. Our attention is more precisely
focused on the choked flow phenomenon which occurs along the mixing chamber of the secondary nozzle and which can be visualized
by CFD. Laser tomography visualizations are used to validate the CFD model. The evolution of flow configuration in the ejector
with the primary stagnation pressure is examined both in the case of zero secondary flow and in the case of free entrainment
of induced air. 相似文献
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The paper presents the numerical simulation results of the surface roughness influence on gas-dynamic processes inside flow parts of a supersonic ejector. These simulations are performed using two commercial CFD solvers (Star- CCM+ and Fluent). The results are compared to each other and verified by a full-scale experiment in terms of global flow parameters (the entrainment ratio: the ratio between secondary to primary mass flow rate - ER hereafter) and local flow parameters distribution (the static pressure distribution along the mixing chamber and diffuser walls). A detailed comparative study of the employed methods and approaches in both CFD packages is carried out in order to estimate the roughness effect on the logarithmic law velocity distribution inside the boundary layer. Influence of the surface roughness is compared with the influence of the backpressure (static pressure at the ejector outlet). It has been found out that increasing either the ejector backpressure or the surface roughness height, the shock position displaces upstream. Moreover, the numerical simulation results of an ejector with rough walls in the both CFD solvers are well quantitatively agreed with each other in terms of the mean ER and well qualitatively agree in terms of the local flow parameters distribution. It is found out that in the case of exceeding the “critical roughness height” for the given boundary conditions and ejector’s geometry, the ejector switches to the “off-design” mode and its performance decreases considerably. 相似文献
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搭建了二维超-超引射器实验系统,进行了二次喉道型式引射器启动特性和负载特性实验,获得了引射器混合室内流场纹影图,结果表明:超声速引射器临界启动状态下,混合室内存在反压引起的激波系;引射器完全启动状态下,主激波系可始于混合室后段,无需被完全吞入二次喉道内;二次流对引射器启动有助推效果,可使混合室内激波系后移;一次流对二次流有压缩作用,且一次流工作压力越高,压缩作用越强;一次流、二次流之间会形成明显的混合层,当一次流、二次流静压不匹配时,一次流喷管出口内端壁处将形成较强斜激波,其在固壁与混合层之间反射、交叉,并向下游延伸,会降低一次流引射性能。 相似文献
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A. V. Sobolev 《Thermophysics and Aeromechanics》2013,20(3):273-276
An experimental investigation of the influence of mixing intensification by small-size jets on the startup and characteristics of a gas ejector with central nozzle and a convergent mixing chamber is carried out. It is shown that at high flow rates of the secondary gas, the critical regime is not settled because of the formation of a thick subsonic layer near the chamber wall. In these cases, a stepwise startup was done. The range of critical regimes is limited by the reloading point, at which the velocity near the chamber wall becomes sonic. The critical regime breakdown behind the reloading point occurs due to the upstream propagation of the back pressure through the subsonic layer. The mixing intensification ensures the equalization of the velocity profile and the extension of the range of critical regimes. Despite the improvement of characteristics the mixing in an ejector with the central nozzle remains incomplete. Experimental characteristics are compared with the computed ones. The mixing process is isobaric in the computation without the consideration of dissipative losses because of which the rise of the pressure of a mixture of primary and secondary gases occurs. 相似文献