Electro Thermal Modeling of the Micro Flow Sensor With Feedback Control Circuit Using SPICE

2007 ◽  
Author(s):  
Shoji Kamiunten ◽  
Hidetomo Nagayo ◽  
Masahiro Motosuke ◽  
Shinji Honami
Keyword(s):  
Fluid Flow ◽  
Integrated Circuit ◽  
Thermal Modeling ◽  
Three Dimensional ◽  
Electric Circuit ◽  
General Purpose ◽  
Flow Sensor ◽  
Spanwise Direction ◽  
Two Dimensional ◽  
Micro Flow

This paper reports an efficient electro-thermal modeling technique for the Micro Flow Sensor (MFS) having an ensured thermal insulation structure with a thin silicon nitride membrane. Both the thermal fluid flow around two-heater MFS and the electric circuit were modeled together using a commercial general-purpose circuit simulator based on SPICE (Simulation Program with Integrated Circuit Emphasis). Two-dimensional laminar Poiseuille channel flow was assumed as the flow field in the model. Remarkable features of this technique are as follows: a partial three-dimensional lumped thermal network model involved in a two dimensional one, single segment for spanwise direction, and the forced convective heat transfer calculated by energy balance at each node in the fluid flow. The simulation and measurement results on the sensor characteristics were in good agreement.

The Aerodynamics of Three-Dimensional Vaned Diffusers in Industrial Centrifugal Compressors

2005 ◽  
Author(s):  
Ahmed Abdelwahab
Keyword(s):  
Centrifugal Compressor ◽  
Dynamic Pressure ◽  
Three Dimensional ◽  
Pressure Recovery ◽  
Navier Stokes ◽  
Spanwise Direction ◽  
Two Dimensional ◽  
Blade Loading ◽  
Recovery Capacity ◽  
Close Proximity

Vaned diffusers have been used successfully as efficient and compact dynamic pressure recovery devices in industrial centrifugal compressor stages. Typically such diffusers consist of a cascade of two-dimensional blades distributed circumferentially at close proximity to the impeller exit. In this paper three low-solidity diffuser blade geometries are numerically investigated. The first geometry employs variable stagger stacking of similar blade sections along the blade span. The second employs linearly inclined stacking to generate blade lean along the diffuser span. The third geometry employs the conventional two-dimensional low-solidity diffuser geometry with no variable stagger or lean. The variable stagger blade arrangement has the potential of better aligning the diffuser leading edges with the highly non-uniform flow leaving the impeller. Both variable stagger and linearly leaned diffuser blade arrangements, however, have the effect of redistributing the blade loading and flow streamlines in the spanwise direction leading to improved efficiency and pressure recovery capacity of the diffuser. In this paper a description of the proposed diffuser geometries is presented. The results of Three-dimensional Navier-Stokes numerical simulations of the three centrifugal compressor arrangements are discussed. Comparisons between the performance of the two and three-dimensional diffuser blade geometries are presented. The comparisons indeed show that the variable stagger and leaned diffusers present an improvement in the diffuser operating range and pressure recovery capacity over the conventional two-dimensional diffuser geometry.

scholarly journals The Two Dimensional Representation of Three Dimensional Interferometer Measurements

1979 ◽  
Vol 49 ◽  
pp. 19-26
Author(s):  
R.H. Frater
Keyword(s):  
Three Dimensional ◽  
General Purpose ◽  
Two Dimensions ◽  
Two Dimensional ◽  
Dimensional Representation ◽  
General Purpose Computer ◽  
Efficient Processing ◽  
Purpose Computer

SummaryA convolution technique for the reduction of three dimensional interferometer measurements to two dimensions is described. With the addition of relatively simple hardware to a general purpose computer the technique allows fast, efficient processing of three dimensional data.

Multiscale reservoir surveillance and monitoring

2021 ◽  
Vol 40 (5) ◽  
pp. 383-384
Author(s):  
Mohammed Badri ◽  
Ali Yousif ◽  
Maged Mabrook
Keyword(s):  
Fluid Flow ◽  
Seismic Data ◽  
Three Dimensional ◽  
Oil Reservoirs ◽  
Two Dimensional ◽  
Sweep Efficiency ◽  
Fluid Movement ◽  
Integrate Data ◽  
Fluid Imaging

Geoscientists and reservoir engineers are challenged to integrate data of different scales to better understand fluid movement in oil reservoirs. Different technologies are capable of imaging fluid movement in the reservoir at different scales. Two-dimensional fluid imaging has been achieved recently through crosswell and surface-to-borehole electromagnetic (EM) measurements. Three-dimensional fluid movement imaging has shown potential by using surface seismic data volumes. The Multiscale Reservoir Surveillance and Monitoring Workshop, held virtually 7–9 December 2020, attempted to address the challenge of how to integrate these measurements obtained at different scales into a workflow to improve the understanding of fluid flow, which is critical for sweep efficiency and recovery.

Spatio-temporal dynamics of a periodically driven cavity flow

2003 ◽  
Vol 478 ◽  
pp. 197-226 ◽  
Author(s):  
M. J. VOGEL ◽  
A. H. HIRSA ◽  
J. M. LOPEZ
Keyword(s):  
Free Surface ◽  
Stokes Equations ◽  
Temporal Dynamics ◽  
Three Dimensional ◽  
Spanwise Direction ◽  
Two Dimensional ◽  
Measured Velocity ◽  
Time Symmetry ◽  
Time Flow ◽  
Time Periodic

The flow in a rectangular cavity driven by the sinusoidal motion of the floor in its own plane has been studied both experimentally and computationally over a broad range of parameters. The stability limits of the time-periodic two-dimensional base state are of primary interest in the present study, as it is within these limits that the flow can be used as a viable surface viscometer (as outlined theoretically in Lopez & Hirsa 2001). Three flow regimes have been found experimentally in the parameter space considered: an essentially two-dimensional time-periodic flow, a time-periodic three-dimensional flow with a cellular structure in the spanwise direction, and a three-dimensional irregular (in both space and time) flow. The system poses a space–time symmetry that consists of a reflection about the vertical mid-plane together with a half-period translation in time (RT symmetry); the two-dimensional base state is invariant to this symmetry. Computations of the two-dimensional Navier–Stokes equations agree with experimentally measured velocity and vorticity to within experimental uncertainty in parameter regimes where the flow is essentially uniform in the spanwise direction, indicating that in this cavity with large spanwise aspect ratio, endwall effects are small and localized for these cases. Two classes of flows have been investigated, one with a rigid no-slip top and the other with a free surface. The basic states of these two cases are quite similar, but the free-surface case breaks RT symmetry at lower forcing amplitudes, and the structure of the three-dimensional states also differs significantly between the two classes.

scholarly journals Numerical and Experimental Study of Topographic Speed-Up Effects in Complex Terrain

Energies ◽  
2020 ◽  
Vol 13 (15) ◽  
pp. 3896 ◽  
Author(s):  
Takanori Uchida ◽  
Kenichiro Sugitani
Keyword(s):  
Wind Tunnel ◽  
Complex Terrain ◽  
Three Dimensional ◽  
Wind Tunnel Experiment ◽  
Dimensional Structure ◽  
Spanwise Direction ◽  
Two Dimensional ◽  
Wind Tunnel Experiments ◽  
Wire Probe ◽  
The Difference

Our research group is developing computational fluid dynamics (CFD)-based software for wind resource and energy production assessments in complex terrain called RIAM-COMPACT (Research Institute for Applied Mechanics, Kyushu University (RIAM)-Computational Prediction of Airflow over Complex Terrain), based on large eddy simulation (LES). In order to verify the prediction accuracy of RIAM-COMPACT, we conduct a wind tunnel experiment that uses a two-dimensional steep ridge model with a smooth surface. In the wind tunnel experiments, airflow measurements are performed using an I-type hot-wire probe and a split film probe that can detect forward and reverse flows. The results of the numerical simulation by LES are in better agreement with the wind tunnel experiment using the split film probe than the results of the wind tunnel experiment using the I-type hot wire probe. Furthermore, we calculate that the two-dimensional ridge model by changing the length in the spanwise direction, and discussed the instantaneous flow field and the time-averaged flow field for the three-dimensional structure of the flow behind the model. It was shown that the eddies in the downwind flow-separated region formed behind the two-dimensional ridge model were almost the same size in all cases, regardless of the difference in the length in the spanwise direction. In this study, we also perform a calculation with a varying inflow shear at the inflow boundary. It was clear that the size in the vortex region behind the model was almost the same in all the calculation results, regardless of the difference in the inflow shear. Next, we conduct wind tunnel experiments on complex terrain. In the wind tunnel experiments using a 1/2800 scale model, the effect of artificial irregularities on the terrain surface did not significantly appear on the airflow at the hub height of the wind turbine. On the other hand, in order to investigate the three-dimensional structure of the airflow in the swept area in detail, it was clearly shown that LES using a high-resolution computational grid is very effective.

INCOMPRESSIBLE FLUIDS

2005 ◽  
Vol 20 (27) ◽  
pp. 6122-6132 ◽  
Author(s):  
S. G. RAJEEV
Keyword(s):  
Fluid Flow ◽  
Incompressible Fluid ◽  
Quantum Groups ◽  
Three Dimensional ◽  
Incompressible Fluids ◽  
Two Dimensional ◽  
Incompressible Fluid Flow ◽  
Fluid System ◽  
Random Forces ◽  
Turbulent Incompressible Fluid

We propose a model for random forces in a turbulent incompressible fluid by balancing the energy gain from fluctuations against dissipation by viscosity. This leads to a more singular covariance distribution for the random forces than is ordinarily allowed. We then propose regularization of the fluid system by matrix models. A formula for entropy of a two dimensional fluid is derived and then a vorticity profile of a hurricane that maximizes entropy. A regularization of three dimensional incompressible fluid flow using quantum groups is also proposed.

CFD High L/D Riser Modeling Study

2007 ◽  
Author(s):  
Yiannis Constantinides ◽  
Owen H. Oakley ◽  
Samuel Holmes
Keyword(s):  
Fluid Flow ◽  
Computer Technology ◽  
Deep Water ◽  
Structural Model ◽  
Three Dimensional ◽  
Two Dimensional ◽  
Flow Simulations ◽  
Dimensional Flow ◽  
Two Dimensional Flow ◽  
Good Agreement

Fully three dimensional fluid flow simulations are used with a simple structural model to simulate very long risers. This method overcomes many shortcomings of methodologies based on two dimensional flow simulations and can correctly include the effects of three dimensional structures such as strakes, buoyancy modules and catenary riser shapes. The method is benchmarked against laboratory and offshore experiments with model risers of length to diameter ratios up to 4,000. RMS values of vortex induced vibration motions are shown to be in good agreement with measurements. The resources needed to model ultra deep water drilling and production risers are estimated based on current computer technology.

Direct numerical simulation of a three-dimensional temporal mixing layer with particle dispersion

1998 ◽  
Vol 358 ◽  
pp. 61-85 ◽  
Author(s):  
WEI LING ◽  
J. N. CHUNG ◽  
T. R. TROUTT ◽  
C. T. CROWE
Keyword(s):  
Large Scale ◽  
Initial Perturbation ◽  
Mixing Layer ◽  
Three Dimensional ◽  
Particle Dispersion ◽  
Spanwise Direction ◽  
Two Dimensional ◽  
Streamwise Direction ◽  
Large Scale Structures ◽  
Scale Structures

The three-dimensional mixing layer is characterized by both two-dimensional and streamwise large-scale structures. Understanding the effects of those large-scale structures on the dispersion of particles is very important. Using a pseudospectral method, the large-scale structures of a three-dimensional temporally developing mixing layer and the associated dispersion patterns of particles were simulated. The Fourier expansion was used for spatial derivatives due to the periodic boundary conditions in the streamwise and the spanwise directions and the free-slip boundary condition in the transverse direction. A second-order Adam–Bashforth scheme was used in the time integration. Both a two-dimensional perturbation, which was based on the unstable wavenumbers of the streamwise direction, and a three-dimensional perturbation, derived from an isotropic energy spectrum, were imposed initially. Particles with different Stokes numbers were traced by the Lagrangian approach based on one-way coupling between the continuous and the dispersed phases.The time scale and length scale for the pairing were found to be twice those for the rollup. The streamwise large-scale structures develop from the initial perturbation and the most unstable wavelength in the spanwise direction was found to be about two thirds of that in the streamwise direction. The pairing of the spanwise vortices was also found to have a suppressing effect on the development of the three-dimensionality. Particles with Stokes number of the order of unity were found to have the largest concentration on the circumference of the two-dimensional large-scale structures. The presence of the streamwise large-scale structures causes the variation of the particle concentrations along the spanwise and the transverse directions. The extent of variation also increases with the development of the three-dimensionality, which results in the ‘mushroom’ shape of the particle distribution.

Three-Dimensional Steady-State String Motion in a Fluid Flow

2004 ◽  
Vol 71 (6) ◽  
pp. 894-895
Author(s):  
Roman Miroshnik
Keyword(s):  
Fluid Flow ◽  
Steady State ◽  
Three Dimensional ◽  
Initial Approximation ◽  
Invariant Curve ◽  
Perturbation Scheme ◽  
Two Dimensional ◽  
Flowing Medium ◽  
Steady State Motion ◽  
Existence Conditions

The phenomenon of three-dimensional (3D) steady-state motion of a string traveling along an invariant curve in a flowing medium is studied. Existence conditions are found using a perturbation scheme where a known two-dimensional (2D) solution is used as an initial approximation.

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