scholarly journals Investigation of Pressure Oscillation and Cavitation Characteristics for Submerged Self-Resonating Waterjet

2021 ◽  
Vol 11 (15) ◽  
pp. 6972
Author(s):  
Lihua Cui ◽  
Fei Ma ◽  
Tengfei Cai
Keyword(s):  
Sudden Change ◽  
Three Dimensional ◽  
Pressure Oscillation ◽  
Experimental Tests ◽  
Low Pressure ◽  
The Self ◽  
Two Phase ◽  
Cavitation Phenomenon ◽  
Pressure Zone ◽  
Unsteady Characteristics

The cavitation phenomenon of the self-resonating waterjet for the modulation of erosion characteristics is investigated in this paper. A three-dimensional computational fluid dynamics (CFD) model was developed to analyze the unsteady characteristics of the self-resonating jet. The numerical model employs the mixture two-phase model, coupling the realizable turbulence model and Schnerr–Sauer cavitation model. Collected data from experimental tests were used to validate the model. Results of numerical simulations and experimental data frequency bands obtained by the Fast Fourier transform (FFT) method were in very good agreement. For better understanding the physical phenomena, the velocity, the pressure distributions, and the cavitation characteristics were investigated. The obtained results show that the sudden change of the flow velocity at the outlet of the nozzle leads to the forms of the low-pressure zone. When the pressure at the low-pressure zone is lower than the vapor pressure, the cavitation occurs. The flow field structure of the waterjet can be directly perceived through simulation, which can provide theoretical support for realizing the modulation of the erosion characteristics, optimizing nozzle structure.

scholarly journals Caracterización del IHX en un sistema de refrigeración automotriz y el COP con refrigerante R134A

2017 ◽  
Vol 2 (1) ◽  
pp. 45
Author(s):  
Bolívar Cuaical ◽  
Paúl Montúfar
Keyword(s):  
High Pressure ◽  
Standard Deviation ◽  
Heat Exchangers ◽  
Cooling System ◽  
Experimental Tests ◽  
Low Pressure ◽  
Coefficient Of Performance ◽  
Pressure Line ◽  
Pressure Zone ◽  
R 134A

The present work has the objective of characterizing several coaxial heat exchanger geometries in an automotive cooling system and its effect on the performance coefficient, using R-134a as refrigerant by means of experimental tests. In the first instance, the experimental tests were carried out with different geometries of coaxial interchanges involved in the high-pressure line between the condenser and the expansion valve, as well as the low pressure line between the evaporator and the compressor, Between the volume of the exchanger and the coefficient of performance by means of a multifactorial analysis. The development of the research entails complying with parameters for the acquisition of experimental data and the development of an adequate experimental design.  Statistical regressions  were  developed  with  R2  of  86.86%  and  a standard deviation of 2.2 for the low-pressure zone, while for the high pressure zone The regression determined a R2 of 95.17% and a standard deviation of 0.57. As for the COP and the T variables is statistically significant with a value of R2 of 99.97%, thus helping to design the heat exchangers to decrease fuel consumption in vehicles. Index Terms— : IHX,COP, R-134a, Cooling cycle Automotive, heat exchangers

Two-Phase Eulerian/Lagrangian Model for Nucleating Steam Flow

2002 ◽  
Vol 124 (2) ◽  
pp. 465-475 ◽  
Author(s):  
A. G. Gerber
Keyword(s):  
Three Dimensional ◽  
Low Pressure ◽  
Steam Flow ◽  
Nucleation Theory ◽  
Lagrangian Model ◽  
Classical Nucleation Theory ◽  
Navier Stokes ◽  
Steam Turbines ◽  
Complex Flow ◽  
Two Phase

This paper describes an Eulerian/Lagrangian two-phase model for nucleating steam based on classical nucleation theory. The model provides an approach for including spontaneous homogeneous nucleation within a full Navier-Stokes solution scheme where the interaction between the liquid and gas phases for a pure fluid is through appropriately modeled source terms. The method allows for the straightforward inclusion of droplet heat, mass, and momentum transfer models along with nucleation within complex flow systems as found, for example, in low pressure steam turbines. The present paper describes the solution method, emphasizing that the important features of nucleating steam flow are retained through comparison with well-established 1-D solutions for Laval nozzle flows. Results for a two-dimensional cascade blade and three-dimensional low pressure turbine stage are also described.

Origami-Based Self-Folding Structure Design and Fabrication Using Projection Based Stereolithography

2015 ◽  
Vol 137 (2) ◽  
Author(s):  
Dongping Deng ◽  
Yong Chen
Keyword(s):  
3D Structure ◽  
Three Dimensional ◽  
Experimental Tests ◽  
Middle Layer ◽  
Structure Design ◽  
The Self ◽  
Two Dimensional ◽  
Polystyrene Film ◽  
Folding Structure ◽  
Unique Capability

Self-folding structures have unique capability such as reconfiguration during their usage. Such capability can be beneficial for a wide variety of applications including biomedical and electronics products. In this paper, a novel fabrication approach based on a three-dimensional (3D) printing process is presented for fabricating self-folding structures that can be actuated in a heating environment. The thermo-actuating structures that are designed and fabricated by our method are two-dimensional (2D) origami sheets, which have multiple printed layers. The middle layer of an origami sheet is a prestrained polystyrene film with large shrinkage ratios when heated. Both its top and bottom surfaces are covered with cured resin that is printed in designed shapes. A foldable hinge is achieved by constraining the shrinkage of the film on one side while allowing the shrinkage of the film on another side when the origami sheet is exposed to a heating environment. Heuristic models of hinge's folding angles are developed based on the related folding mechanism. A 2D origami sheet design and fabrication method is presented for a given 3D structure. Various experimental tests are performed to verify the self-folding performance of the designed and fabricated origami sheets. Techniques on improving folding angle control are also discussed with possible applications.

Nanoscale Self-Assembly Using Ion and Electron Beam Techniques: A Rapid Review

MRS Advances ◽  
2020 ◽  
Vol 5 (64) ◽  
pp. 3507-3520
Author(s):  
Chunhui Dai ◽  
Kriti Agarwal ◽  
Jeong-Hyun Cho
Keyword(s):  
Electron Beam ◽  
Self Assembly ◽  
Ion Beam ◽  
Three Dimensional ◽  
The Self ◽  
Stress Generation ◽  
Rapid Review ◽  
High Yield ◽  
3D Nanostructures ◽  
Self Assembled

AbstractNanoscale self-assembly, as a technique to transform two-dimensional (2D) planar patterns into three-dimensional (3D) nanoscale architectures, has achieved tremendous success in the past decade. However, an assembly process at nanoscale is easily affected by small unavoidable variations in sample conditions and reaction environment, resulting in a low yield. Recently, in-situ monitored self-assembly based on ion and electron irradiation has stood out as a promising candidate to overcome this limitation. The usage of ion and electron beam allows stress generation and real-time observation simultaneously, which significantly enhances the controllability of self-assembly. This enables the realization of various complex 3D nanostructures with a high yield. The additional dimension of the self-assembled 3D nanostructures opens the possibility to explore novel properties that cannot be demonstrated in 2D planar patterns. Here, we present a rapid review on the recent achievements and challenges in nanoscale self-assembly using electron and ion beam techniques, followed by a discussion of the novel optical properties achieved in the self-assembled 3D nanostructures.

UNSTEADY CHARACTERISTICS OF TWO PHASE FLOW IN A HORIZONTAL TUBE EVAPORATOR

1974 ◽  
Author(s):  
Takamoto Saito ◽  
Hideo Uchida ◽  
Eiichi Hiraoka
Keyword(s):  
Two Phase Flow ◽  
Horizontal Tube ◽  
Phase Flow ◽  
Two Phase ◽  
Unsteady Characteristics

Simulating Self-Regeneration and Self-Replication Processes Using Movable Cellular Automata with a Mutual Equilibrium Neighborhood

2020 ◽  
Vol 29 (4) ◽  
pp. 741-757
Author(s):  
Kateryna Hazdiuk ◽  
◽  
Volodymyr Zhikharevich ◽  
Serhiy Ostapov ◽  
◽  
...  
Keyword(s):  
Cellular Automata ◽  
Cellular Automaton ◽  
Three Dimensional ◽  
Computer Models ◽  
The Self ◽  
Model Construction ◽  
Natural Phenomena ◽  
Different Types ◽  
Movable Cellular Automata ◽  
Self Replication

This paper deals with the issue of model construction of the self-regeneration and self-replication processes using movable cellular automata (MCAs). The rules of cellular automaton (CA) interactions are found according to the concept of equilibrium neighborhood. The method is implemented by establishing these rules between different types of cellular automata (CAs). Several models for two- and three-dimensional cases are described, which depict both stable and unstable structures. As a result, computer models imitating such natural phenomena as self-replication and self-regeneration are obtained and graphically presented.

Experimental study on saturated boiling of two phase natural circulation under low pressure in narrow rectangular channels

Kerntechnik ◽  
2017 ◽  
Vol 82 (6) ◽  
pp. 631-636
Author(s):  
Li Zi-chao ◽  
Qi Shi ◽  
Zhou Tao ◽  
Li Bing ◽  
Muhammad Ali Shahzad ◽  
...  
Keyword(s):  
Experimental Study ◽  
Natural Circulation ◽  
Low Pressure ◽  
Two Phase ◽  
Rectangular Channels ◽  
Saturated Boiling

scholarly journals Detecting the Mechanism behind the Transition from Fixed Two-Dimensional Patterned Sika Deer (Cervus nippon) Dermal Papilla Cells to Three-Dimensional Pattern

2021 ◽  
Vol 22 (9) ◽  
pp. 4715
Author(s):  
Guanning Wei ◽  
Hongmei Sun ◽  
Haijun Wei ◽  
Tao Qin ◽  
Yifeng Yang ◽  
...  
Keyword(s):  
Culture Condition ◽  
Sika Deer ◽  
Three Dimensional ◽  
Cervus Nippon ◽  
Dermal Papilla ◽  
Growth Patterns ◽  
The Self ◽  
Dermal Papilla Cells ◽  
Aggregative Behavior ◽  
Cell Pattern

The hair follicle dermal papilla is critical for hair generation and de novo regeneration. When cultured in vitro, dermal papilla cells from different species demonstrate two distinguishable growth patterns under the conventional culture condition: a self-aggregative three dimensional spheroidal (3D) cell pattern and a two dimensional (2D) monolayer cell pattern, correlating with different hair inducing properties. Whether the loss of self-aggregative behavior relates to species-specific differences or the improper culture condition remains unclear. Can the fixed 2D patterned dermal papilla cells recover the self-aggregative behavior and 3D pattern also remains undetected. Here, we successfully constructed the two growth patterns using sika deer (Cervus nippon) dermal papilla cells and proved it was the culture condition that determined the dermal papilla growth pattern. The two growth patterns could transit mutually as the culture condition was exchanged. The fixed 2D patterned sika deer dermal papilla cells could recover the self-aggregative behavior and transit back to 3D pattern, accompanied by the restoration of hair inducing capability when the culture condition was changed. In addition, the global gene expressions during the transition from 2D pattern to 3D pattern were compared to detect the potential regulating genes and pathways involved in the recovery of 3D pattern and hair inducing capability.

scholarly journals Three-Dimensional Analysis of the In Vivo Motion of Implantable Cardioverter Defibrillator Leads

2021 ◽  
Author(s):  
Tamas Szili-Torok ◽  
Jens Rump ◽  
Torsten Luther ◽  
Sing-Chien Yap
Keyword(s):  
Three Dimensional ◽  
Second Phase ◽  
Two Phase ◽  
Maximum Curvature ◽  
Phase Study ◽  
Absolute Curvature ◽  
Icd Leads ◽  
Lead Testing ◽  
Design And Testing

Abstract Better understanding of the lead curvature, movement and their spatial distribution may be beneficial in developing lead testing methods, guiding implantations and improving life expectancy of implanted leads. Objective The aim of this two-phase study was to develop and test a novel biplane cine-fluoroscopy-based method to evaluate input parameters for bending stress in leads based on their in vivo 3D motion using precisely determined spatial distributions of lead curvatures. Potential tensile, compressive or torque forces were not subjects of this study. Methods A method to measure lead curvature and curvature evolution was initially tested in a phantom study. In the second phase using this model 51 patients with implanted ICD leads were included. A biplane cine-fluoroscopy recording of the intracardiac region of the lead was performed. The lead centerline and its motion were reconstructed in 3D and used to define lead curvature and curvature changes. The maximum absolute curvature Cmax during a cardiac cycle, the maximum curvature amplitude Camp and the maximum curvature Cmax@amp at the location of Camp were calculated. These parameters can be used to characterize fatigue stress in a lead under cyclical bending. Results The medians of Camp and Cmax@amp were 0.18 cm−1 and 0.42 cm−1, respectively. The median location of Cmax was in the atrium whereas the median location of Camp occurred close to where the transit through the tricuspid valve can be assumed. Increased curvatures were found for higher slack grades. Conclusion Our results suggest that reconstruction of 3D ICD lead motion is feasible using biplane cine-fluoroscopy. Lead curvatures can be computed with high accuracy and the results can be implemented to improve lead design and testing.

Sign in / Sign up

Export Citation Format

Share Document