Converging flow analysis, entrance pressure drops, and vortex sizes: Measurements and calculated values

2001 ◽  
Vol 41 (12) ◽  
pp. 2095-2107 ◽  
Author(s):  
Christian Carrot ◽  
Jacques Guillet ◽  
Ren� Fulchiron
Keyword(s):  
Flow Analysis ◽  
Pressure Drops ◽  
Converging Flow ◽  
Entrance Pressure

Improvements to an Air Bypass System on a Kawasaki M1A-13X Engine

2004 ◽  
Author(s):  
Suresh R. Vilayanur ◽  
John Battaglioli
Keyword(s):  
Flow Analysis ◽  
Effective Area ◽  
Inlet Temperature ◽  
Flow Area ◽  
Detailed Measurement ◽  
Pressure Drops ◽  
Operating Range ◽  
Flow Losses ◽  
Catalytic Combustor ◽  
Improved Design

A new bypass system using an improved design has been fabricated and tested on a Kawasaki M1A-13X gas turbine engine. The engine and catalytic combustor are currently installed at the City of Santa Clara’s Silicon Valley Power municipal electrical generating stations and connected to the utility grid. The use of a bypass system with a catalytic combustor, incorporating the Xonon Cool Combustion™ technology, on an M1A-13X system increases the low emissions load turndown and ambient operating range without impacting engine efficiency. The increased operating range is achieved because the bypass system provides the required adiabatic combustion temperature (Tad) in the combustor’s post-catalyst burn out zone without changing the turbine inlet temperature. A detailed measurement of the pressure drops, in the old bypass system, revealed that there were large flow losses present, particularly in the re-injection spool piece and the extraction plenum. Since it was determined that the spool had the highest pressure loss, this was the component targeted for improvement. The analysis coupled with detailed measurements on the reinjection piece revealed that the effective area actually varied with flow As the flow changed, so did the flow mechanics inside and exiting the spool piece. Therefore, in order to achieve the design target, the flow area of the spool piece had to be optimized at the predicted capacity flow rate. CFD analysis of the spool piece revealed the regions of losses in the re-injection piece. This analysis along with a one-dimensional flow analysis of the entire system enabled the design of new spool re-injection piece. Once the design was completed, the new bypass system was fabricated and tested. Bypass flow capacity was increased by about 22%. This was achieved by alleviating regions of flow losses and also by using a new “scoop” design for the bypass reinjection tubes. As expected, engine turndown capacity and ambient operating range were improved with the new design.

Fluid-Structure Interaction Modeling and Validation of Idealized Left Ventricular Blood Flow

2020 ◽  
Author(s):  
Megan Laughlin ◽  
Sam Stephens ◽  
Hanna Jensen ◽  
Morten Jensen ◽  
Paul Millett
Keyword(s):  
Blood Flow ◽  
Fluid Structure Interaction ◽  
Flow Analysis ◽  
Left Ventricular ◽  
Maximum Pressure ◽  
Flow Loop ◽  
Fluid Structure ◽  
Pressure Drops ◽  
Structure Interaction ◽  
Custom Made

Abstract Fluid Structure Interaction (FSI) models are an essential tool in understanding the complex coupling of blood flow in the heart. The objective of this study is to establish a method of comparing data obtained from FSI models and benchtop measurements from phantoms to identify sources of flow changes for use in intraventricular flow analysis. Two geometries are considered: 1) a vascular model consisting of a straight channel with an ellipsoidal swell and 2) an idealized left ventricle (LV) model representative “acorn” shape. Two phantoms are created for each of the two geometries: 3D printed rigid phantoms from a resin and custom-made tissue-mimicking phantoms from a medical gel. Benchtop measurements are made using the phantoms within a custom flow loop setup with pulsatile flow. Computational Fluid Dynamics (CFD) simulations are conducted with a Smoothed Particle Hydrodynamics (SPH) model. The two flow channel geometries utilized in the experiments are replicated for the simulations. The cavity walls are defined by ghost particles that are rigidly fixed. Maximum pressure drops were 57 mmHg and 196 mmHg for the rigid swell and rigid LV, respectively, whereas maximum pressure drops were 155 mmHg for the gel swell and 140 mmHg for the gel LV. Calculations from the simulations resulted in a maximum pressure drop of 55 mmHg for the swell and 110 mmHg for the LV. This data serves as a first step in corroborating our methodology to utilize the information obtained from both methods to identify and better understand mutual sources of changes in flow patterns.

Flow Induced Dynamics of Plate Seals

2019 ◽  
Author(s):  
Deepak Trivedi ◽  
Bernardo Kerr
Keyword(s):  
High Speed ◽  
Phase Locking ◽  
Flow Analysis ◽  
Feedback Mechanism ◽  
Experimental Methodology ◽  
Dynamical Instability ◽  
Amplitude Death ◽  
Flow Induced Vibration ◽  
Center Manifold Reduction ◽  
Pressure Drops

Abstract Plate seals can provide low leakage at rotor-stator interfaces with large pressure drops in turbomachinery within a limited axial span. When designed with a self-correcting hydrostatic feedback mechanism, non-contact operation could be achieved even in the presence of large rotor transients. Flow induced dynamical instability is one of the key design challenges in plate seals for rotor-stator sealing in turbomachinery. The instabilities are caused by potentially multiple flow induced vibration mechanisms operating during different flow regimes. This paper investigates mechanisms of vortex induced flutter in compliant plate seals, which happens when the vortex shedding frequency of the plates comes close to one of the natural frequencies of vibration of the structure. An experimental methodology based on optical flow analysis of high speed videography is proposed to characterize vibrations of the ensemble of plates (“leafpack”.) Experiments show that the compliant plates vibrate in the flow field with amplitude dependent on the pressure drop. Additionally, the vibrations of individual plates are highly coupled to each other, leading to phase-locking or phase-drifting depending on boundary conditions. The leafpack has a characteristic frequency and exhibits traveling wave phenomena under certain conditions of pressurization. Using experimental insights, plate seals are modeled as a ring of a large (∼103) number of locally coupled oscillators, with nonlinear stiffness arising from hydrostatic forces. A two-way coupling exists between the structural and fluid wake dynamics. Using center manifold reduction, the coupled fourth order dynamics of the system is reduced to second order and transform the equations into the normal form for investigating the possibility of mitigating flow induced vibrations through the phenomenon of amplitude death. Conditions under which successful induction of amplitude death could eliminate plate vibration in the mode under consideration is discussed.

Flow Analysis in Pipe of a Manifold Block

2012 ◽  
Vol 6 (4) ◽  
pp. 494-501 ◽  
Author(s):  
Osamu Abe ◽  
◽  
Tetsuhiro Tsukiji ◽  
Takeshi Hara ◽  
Kazutoshi Yasunaga ◽  
...  
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Pipe Flow ◽  
Hydraulic System ◽  
Flow Analysis ◽  
Cfd Analysis ◽  
Hydraulic Systems ◽  
Pressure Drops ◽  
Computational Fluid Dynamics Cfd ◽  
Pipeline Design

Manifold blocks are recently used to connect hydraulic components in hydraulic system, which has flow channel inside. They are useful for reducing the size and weight of hydraulic systems. This paper deals with solid manifold block and laminated manifold block. They are different from machining. We investigate pressure drops of their pipe flow with Computational Fluid Dynamics (CFD) and compare those of two types. And then, we conduct experiment, measuring pressure and visualization, to validate the results of CFD analysis. By using these results, we are intended to obtain guidelines for pipeline design in laminated manifold block.

A New One Dimensional Modeling Method for Complex Oil Passage Coupled With CFD Results

2014 ◽  
Author(s):  
Hiroshi Higo ◽  
Kazuhiro Tanaka ◽  
Takeshi Yamaguchi
Keyword(s):  
Linear Model ◽  
Automatic Transmission ◽  
Flow Analysis ◽  
Three Dimensional ◽  
Inertia Effect ◽  
Pipe Length ◽  
Pressure Drops ◽  
New Model ◽  
The Real ◽  
Pipe Model

Oil pipes are indispensable to a hydraulic circuit. The linear model of pipe based on the Hagen-Poiseuille law is commonly used and very convenient in the analyses. However, real oil passages, such as in manifolds and oil passages in an automatic transmission in a car, have complex configurations. As they are quite three-dimensional and have various kinds of pressure drops on the inside, it is sometimes unsuitable to represent the real oil passages using the linear model. As the result of applying it to the real oil passage, the equivalent pipe length would sometimes be very long unrealistically. Moreover, the inertia effect of oil column in the passage is sometimes non-negligible. This study represents a way to model real oil passages into a dynamically-equivalent pipe model using its CAD data and CFD results. The pressure drop is represented by the non-linear model of pipe and the coefficients are calculated from ΔP-Q curve of the passage which is obtained by CFD steady flow analysis. The inertia effect of oil column is calculated by CFD unsteady flow analysis and its coefficient is obtained from the solution of the differential equation which is expressed by a correlation coefficient. As a result, a new model of pipe is successfully obtained with the same effects of resistance and inertia as the real oil passage. The simulation using the new model of pipe agrees well with the experimental results. This modeling way is applicable to all oil passages with any 3-D configuration.

Production flow analysis

1963 ◽  
Vol 42 (12) ◽  
pp. 742 ◽  
Author(s):  
John L. Burbidge
Keyword(s):  
Flow Analysis ◽  
Production Flow

Review on the aerodynamics of intermediate compressor duct

2020 ◽  
Vol 14 (4) ◽  
pp. 7446-7468
Author(s):  
Manish Sharma ◽  
Beena D. Baloni
Keyword(s):  
High Pressure ◽  
Pressure Loss ◽  
Flow Analysis ◽  
Outer Wall ◽  
Optimization Techniques ◽  
Optimum Pressure ◽  
Research Areas ◽  
Static Pressure Distribution ◽  
High Pressure Compressor ◽  
Pressure Compressor

In a turbofan engine, the air is brought from the low to the high-pressure compressor through an intermediate compressor duct. Weight and design space limitations impel to its design as an S-shaped. Despite it, the intermediate duct has to guide the flow carefully to the high-pressure compressor without disturbances and flow separations hence, flow analysis within the duct has been attractive to the researchers ever since its inception. Consequently, a number of researchers and experimentalists from the aerospace industry could not keep themselves away from this research. Further demand for increasing by-pass ratio will change the shape and weight of the duct that uplift encourages them to continue research in this field. Innumerable studies related to S-shaped duct have proven that its performance depends on many factors like curvature, upstream compressor’s vortices, swirl, insertion of struts, geometrical aspects, Mach number and many more. The application of flow control devices, wall shape optimization techniques, and integrated concepts lead a better system performance and shorten the duct length.  This review paper is an endeavor to encapsulate all the above aspects and finally, it can be concluded that the intermediate duct is a key component to keep the overall weight and specific fuel consumption low. The shape and curvature of the duct significantly affect the pressure distortion. The wall static pressure distribution along the inner wall significantly higher than that of the outer wall. Duct pressure loss enhances with the aggressive design of duct, incursion of struts, thick inlet boundary layer and higher swirl at the inlet. Thus, one should focus on research areas for better aerodynamic effects of the above parameters which give duct design with optimum pressure loss and non-uniformity within the duct.

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