Influence of Cylindrical, k, and ks Diesel Nozzle Shape on the Injector Internal Flow Field and on the Emerging Spray Characteristics

Author(s):  
Federico Brusiani ◽  
Gian Marco Bianchi ◽  
Stefania Falfari ◽  
Angelo Onorati ◽  
Tommaso Lucchini ◽  
...  

2018 ◽  
Vol 144 ◽  
pp. 757-768 ◽  
Author(s):  
Liang Zhao ◽  
Mu Wang ◽  
Peng Wang ◽  
Xiaojing Zhu ◽  
Qinggang Qiu ◽  
...  


1972 ◽  
Vol 94 (4) ◽  
pp. 926-930 ◽  
Author(s):  
R. L. Thornock ◽  
E. F. Brown

Despite the widespread use of convergent-conical nozzles as propulsion nozzles in turbojet aircraft, little attention has been given to the effect of nozzle shape on their propulsive performance. This paper presents the results of an experimental investigation in which the effect of nozzle angle on the internal characteristics of the flow field and on the propulsive performance of convergent conical nozzles was investigated. In addition, a theoretical solution is described which was developed as a part of this investigation. Fifteen, twenty-five, and forty-degree nozzles were tested at pressure ratios from 1.4 to 7.0. Measurements were made of the nozzle discharge coefficient, thrust coefficient, local flow angle, and wall static pressure. The properties of the internal flow field were seen to be affected by the nozzle angle and at pressure ratios less than the choked pressure ratio by the pressure ratio as well. The results of the theoretical analysis substantiate this behavior and are in reasonable agreement with the experimental data.



2016 ◽  
Vol 51 (1) ◽  
pp. 110-116
Author(s):  
Sumito Yokobe ◽  
Katsuyuki Ohsawa ◽  
Tetsuya Oda ◽  
Takahiro Sumi ◽  
Keiichiro Yabuta ◽  
...  


Author(s):  
Eric Savory ◽  
Norman Toy ◽  
Shiki Okamoto ◽  
Yoko Yamanishi


Author(s):  
Weihui Xu ◽  
Xiaoke He ◽  
Xiao Hou ◽  
Zhihao Huang ◽  
Weishu Wang

AbstractCavitation is a phenomenon that occurs easily during rotation of fluid machinery and can decrease the performance of a pump, thereby resulting in damage to flow passage components. To study the influence of wall roughness on the cavitation performance of a centrifugal pump, a three-dimensional model of internal flow field of a centrifugal pump was constructed and a numerical simulation of cavitation in the flow field was conducted with ANSYS CFX software based on the Reynolds normalization group k-epsilon turbulence model and Zwart cavitation model. The cavitation can be further divided into four stages: cavitation inception, cavitation development, critical cavitation, and fracture cavitation. Influencing laws of wall roughness of the blade surface on the cavitation performance of a centrifugal pump were analyzed. Research results demonstrate that in the design process of centrifugal pumps, decreasing the wall roughness appropriately during the cavitation development and critical cavitation is important to effectively improve the cavitation performance of pumps. Moreover, a number of nucleation sites on the blade surface increase with the increase in wall roughness, thereby expanding the low-pressure area of the blade. Research conclusions can provide theoretical references to improve cavitation performance and optimize the structural design of the pump.



Sensors ◽  
2021 ◽  
Vol 21 (3) ◽  
pp. 886
Author(s):  
Cui Dai ◽  
Chao Guo ◽  
Yiping Chen ◽  
Liang Dong ◽  
Houlin Liu

The strong noise generated during the operation of the centrifugal pump harms the pump group and people. In order to decrease the noise of the centrifugal pump, a specific speed of 117.3 of the centrifugal pump is chosen as a research object. The bionic modification of centrifugal pump blades is carried out to explore the influence of different bionic structures on the noise reduction performance of centrifugal pumps. The internal flow field and internal sound field of bionic blades are studied by numerical calculation and test methods. The test is carried out on a closed pump test platform which includes external characteristics and a flow noise test system. The effects of two different bionic structures on the external characteristics, acoustic amplitude–frequency characteristics and flow field structure of a centrifugal pump, are analyzed. The results show that the pit structure has little influence on the external characteristic parameters, while the sawtooth structure has a relatively great influence. The noise reduction effect of the pit structure is aimed at the wide-band noise, while the sawtooth structure is aimed at the discrete noise of the blade-passing frequency (BPF) and its frequency doubling. The noise reduction ability of the sawtooth structure is not suitable for high-frequency bands.



Author(s):  
Takaya Onishi ◽  
H. Sato ◽  
M. Hayakawa ◽  
Y. Kawata

Propeller fans are required not only to have high performance but also to be extremely quiet. The internal flow field of ventilation propeller fans is even more complicated because they usually have a very peculiar configuration with protruding blades upstream. Thus, many kinds of internal vortices yield which cause noise and their cause and countermeasures are needed to be clarified. The purposes of this paper are to visualize the internal flow of the propeller fan from the static and rotating frame of reference. The internal flow visualization measured from the static frame gives approximately the scale of the tip vortex. The visualization from the rotating coordinate system yields a better understanding of the flow phenomena occurring at the specific blade. The experiment is implemented by using a small camera mounted on the shaft of the fan and rotated it to capture the behavior of the vortices using a laser light sheet to irradiate the blade surface. Hence, the flow field of the specific blade could be understood to some extent. The visualized results are compared with the CFD results and these results show a similar tendency about the generation point and developing process of the tip vortex. In addition, it is found that the noise measurement result is relevant to the effect of tip vortex from the visualization result.



2012 ◽  
Vol 621 ◽  
pp. 196-199
Author(s):  
Shui Ping LI ◽  
Ya Li Yuan ◽  
Lu Gang Shi

Numerical simulation method of the internal flow field of fluid machinery has become an important technology in the study of fluid machinery design. In order to obtain a high-performance cement slurry mixer, computational fluid dynamics (CFD) techniques are used to simulate the flow field in the mixer, and the simulation results are studied. According to the analysis results, the structural parameters of the mixer are modified. The results show the mixer under the revised parameters meet the design requirements well. So CFD analysis method can shorten design period and provide valuable theoretical guidance for the design of fluid machinery.



2015 ◽  
Vol 7 (6) ◽  
pp. 168781401558966
Author(s):  
Ma Wenxing ◽  
Liu Hao ◽  
Liu Chunbao ◽  
Liu Changsuo


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