scholarly journals A Theoretical Model for Metal Cation Reduction in the Flow Field and Its Application to Copper Electrorefining

2022 ◽  
pp. ArticleID:220236
Author(s):  
Wenyu Feng ◽  
Keyword(s):  
Theoretical Model ◽  
Flow Field ◽  
Metal Cation ◽  
Copper Electrorefining

Theoretical Model of a Flow in a Tube With a Slit

2019 ◽  
Author(s):  
Yuki Toda ◽  
Masataka Morimatsu ◽  
Yu Nishio ◽  
Takanobu Ogawa
Keyword(s):  
Theoretical Model ◽  
Flow Field ◽  
Pressure Loss ◽  
Longitudinal Direction ◽  
Gas Mixture ◽  
Straight Tube ◽  
One Dimensional ◽  
Tube Type ◽  
Gas Burner

Abstract A tube-type gas burner consists of a straight tube with a slit along it and discharges an air-gas mixture through the slit to produce a flame. The flow velocity from the slit depends on the pressure in the tube and the pressure loss at the slit, and it varies in the longitudinal direction of the tube. The resulting uneven flame degrades the quality of the burner. In this study, we develop a one-dimensional theoretical model of the flow in a tube with a slit. To validate the result of the theoretical model, we also conduct experiments and numerical simulations for the same flow field. We applied this theoretical model to a flow in a tube, 1 m length, 40 mm in diameter, with a slit 2.5 mm wide. The end of the tube is closed. We also discuss the effect of the length of the burner on the unevenness.

Theoretical model for multiple breakup of fluid particles in turbulent flow field

AIChE Journal ◽  
2016 ◽  
Vol 62 (12) ◽  
pp. 4508-4525 ◽  
Author(s):  
Kiyanoosh Razzaghi ◽  
Farhad Shahraki
Keyword(s):  
Theoretical Model ◽  
Flow Field ◽  
Turbulent Flow ◽  
Turbulent Flow Field ◽  
Fluid Particles

A Theoretical Model for Flow Instability Inception in Transonic Fan/Compressors

2013 ◽  
Author(s):  
Xiaofeng Sun ◽  
Xiaohua Liu ◽  
Dakun Sun
Keyword(s):  
Theoretical Model ◽  
Flow Field ◽  
High Speed ◽  
Cfd Simulation ◽  
Flow Instability ◽  
Computational Cost ◽  
Mean Flow ◽  
Transonic Compressor ◽  
Onset Point ◽  
Transonic Fan

This paper applies a theoretical model, which has been developed recently, to calculate the flow instability inception of axial transonic fan/compressors system. After the mean flow field is computed by steady CFD simulation, a body force approach, which is a function of flow field data, is taken to represent the effects of discrete blades on the flow field and duplicate the physical sources of flow turning and loss. Further by applying appropriate boundary conditions and spectral collocation method, a group of homogeneous equations will yield from which the stability equation can be derived. The singular value decomposition method is adopted over a series of fine grids in frequency domain to solve the resultant eigenvalue problem, and the onset point of flow instability can be judged by the imaginary part of the resultant eigenvalue. The present investigation is to validate the feasibility of calculating the stall onset point for single stage transonic compressor. It is shown that this model is capable of predicting instability inception point of transonic flow with reasonable accuracy, and it is sustainable in terms of computational cost for industrial application. It is shown that this model can provide an unambiguous judgment on stall inception without numerous requirements of empirical relations of loss and deviation angle. It provides a possibility to check over-predicted stall margin during the design phase of new high speed fan/compressors. In addition, the effect of flow compressibility on the stall onset point calculation for transonic rotor is studied.

Analysis of flow field characteristics and structure optimization of the split-stream rushing muffler for diesel engine

2020 ◽  
Vol 68 (1) ◽  
pp. 101-111 ◽  
Author(s):  
He Su ◽  
Pei Wu ◽  
Jing Xue ◽  
Yongan Zhang ◽  
Haijun Zhang
Keyword(s):  
Theoretical Model ◽  
Diesel Engine ◽  
Flow Field ◽  
Pressure Loss ◽  
Transmission Loss ◽  
Engineering Application ◽  
Structure Optimization ◽  
Resistance Coefficient ◽  
Tracer Test ◽  
Flow Field Characteristics

In order to analyze the flow field characteristics of the split-stream rushing muffler, a theoretical model describing the velocity of the split streams is established and verified by the tracer test. For this new-principle muffler, the acoustic performance and the relationship between the velocity drop of the airflow and the pressure field are analyzed, also the structure optimization of the muffler is carried out based on the orthogonal test. Finally, a new muffler is fabricated based on the designing theory of this type of muffler for a prototype of diesel engine, and the comparative analyses are conducted compared with its original muffler. The results show that the establishment and analysis of the theoretical model for velocity during the split-streams rushing process are correct. In the frequency range of 0â–“1000 Hz, the average transmission loss of split-stream rushing muffler is better than that of the original muffler. While the speed of airflow is reduced by split-streams rushing, a certain pressure loss is caused at the same time, which is about 50% of total pressure loss of the muffler, and the average fluid resistance coefficient of the split-stream rushing process is 0.91. Compared to the original muffler of the sample engine, the average insertion loss of the optimized new muffler is increased by 61.2%. At inlet air velocity of 30 m/s, the pressure loss is reduced by 16.8%. The results provide a potential for practical engineering application of this new split-stream rushing muffler in future.

scholarly journals Computation of Unsteady Blade Forces in Turbomachines by Means of Potential Flow Theory and by Simulating Viscous Wakes

1982 ◽  
Author(s):  
P. Krammer
Keyword(s):  
Experimental Data ◽  
Theoretical Model ◽  
Velocity Field ◽  
Flow Field ◽  
Potential Flow ◽  
Flow Theory ◽  
The Other ◽  
Potential Flow Theory ◽  
Flow Fluctuations ◽  
Excitation Mechanisms

This paper describes a new theoretical model which computes two main excitation mechanisms, one based on the potential flow theory and the other explainable by the motion of blades through the wakes of preceding blades. The computation of the potential flow field is based on the assumption of a plane, unsteady, incompressible flow. Fluctuations of circulation caused by an alternating velocity field are taken into account by free vortex paths. Blade surfaces are modeled by a vortex distribution. Viscous wakes are simulated by means of contrarotating vortex rows. Results of the theoretical approach are compared with experimental data measured in axial turbomachines.

scholarly journals Effect of chamber diameter of vortex gripper on maximum suction force and flow field

2019 ◽  
Vol 11 (3) ◽  
pp. 168781401983740 ◽  
Author(s):  
Ching Wang ◽  
Jianghong Zhao ◽  
Xin Li
Keyword(s):  
Theoretical Model ◽  
Flow Field ◽  
Pressure Gradient ◽  
Velocity Distribution ◽  
Negative Pressure ◽  
High Speed ◽  
Vortex Chamber ◽  
Experimental Results ◽  
Circumferential Velocity ◽  
Suction Force

The vortex gripper is a non-contact suction device that uses a high-speed rotating airflow to create a negative pressure and suction force. In this research, we studied the effect of the vortex gripper’s diameter on the maximum suction force and internal flow field. First, we proposed a simplified theoretical model of the maximum suction force and predicted the influences of changing the diameter. Then, we obtained the maximum suction forces of the grippers with different diameters through the experiment. Both the theoretical and experimental results show that changing the diameter of the vortex gripper increases the maximum suction force. However, with the increase in the diameter, the prediction of the trend of the maximum suction force is inconsistent with the experimental results. To analyze the difference between the theoretical and experimental results, we further measured the pressure distribution of the vortex gripper and calculated the pressure gradient. The pressure distribution showed that the maximum negative pressure decreases while the diameter increases, and there is a pressure platform, which dominates the central area of the chamber. Next, we indirectly obtained the circumferential velocity distribution based on the relationship between the pressure gradient and circumferential velocity. The results of the circumferential velocity distribution reveal that the high-speed rotating airflow only exists in the area near the inner wall of the vortex chamber, while the circumferential velocity in the central part of the vortex chamber is extremely slow. In addition, the results clarify that the inaccurate assumption of velocity distribution of the simplified theoretical model is the main cause of the theoretical prediction bias.

On the Main Flow Pattern in Hydrocyclones

1993 ◽  
Vol 115 (1) ◽  
pp. 21-25 ◽  
Author(s):  
C. C. Hwang ◽  
H. Q. Shen ◽  
G. Zhu ◽  
M. M. Khonsari
Keyword(s):  
Theoretical Model ◽  
Flow Field ◽  
Closed Form ◽  
Flow Pattern ◽  
Main Flow ◽  
Experimental Measurements ◽  
Main Body ◽  
Governing Equations ◽  
Adequate Representation ◽  
Good Agreement

A theoretical model is developed for the prediction of the main flow pattern in hydrocyclones. The model regards the main body of the cyclone as inviscid and includes provisions for the fluid underflow in cyclones. The governing equations are solved analytically in closed form. To verify the results, a laboratory-scale conically-shaped hydrocyclone was designed, built, and tested. Experimental measurements for axial and tangential velocities are presented with a series of tests solely devoted to the effect of underflow. The theoretical and experimental results are shown to be in good agreement. It is concluded that such an inviscid model gives an adequate representation of the main flow field in a cyclone.

Theoretical model of gravitational perturbation of current collector axisymmetric flow field

1990 ◽  
Vol 67 (10) ◽  
pp. 6099-6108 ◽  
Author(s):  
John S. Walker ◽  
Samuel H. Brown ◽  
Neal A. Sondergaard
Keyword(s):  
Theoretical Model ◽  
Flow Field ◽  
Axisymmetric Flow ◽  
Current Collector ◽  
Gravitational Perturbation
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