An experimental study of the frequency response of electrochemical sensors in nonhomogeneous flow in packed beds

1994 ◽  
Vol 24 (7) ◽  
pp. 639-646 ◽  
Author(s):  
S. Rode ◽  
M. A. Latifi ◽  
A. Storck ◽  
N. Midoux
Keyword(s):  
Experimental Study ◽  
Frequency Response ◽  
Electrochemical Sensors ◽  
Packed Beds ◽  
Nonhomogeneous Flow

An Experimental Study of Heat and Mass Transfer During Drying of Packed Beds

1992 ◽  
Vol 114 (3) ◽  
pp. 727-734 ◽  
Author(s):  
W. C. Lee ◽  
O. A. Plumb ◽  
L. Gong
Keyword(s):  
Mass Transfer ◽  
Experimental Study ◽  
Glass Beads ◽  
Drying Rate ◽  
Packed Beds ◽  
Transfer Coefficients ◽  
Model Predictions ◽  
Drying Models ◽  
Surface Saturation ◽  
Drying Conditions

An experimental study has been conducted to provide a data base for drying packed beds of granular, nonhygroscopic materials. Experimental results for drying rate, saturation distribution, temperature distribution, and surface saturation are reported for drying glass beads under carefully documented drying conditions. Capillary pressure for both imbibition and drainage was measured for the glass beads, whose size ranged from 65 μm to 450 μm. The drying results demonstrate that, contrary to available model predictions, porous materials do not necessarily exhibit saturation gradients that always increase with distance from the drying surface. Under certain conditions the capillary potential is sufficient to create an internal drying front. The measurements of surface saturation are the first to be reported. They are utilized to speculate on the reasons for the failure of drying models to compare well with experiment without adjusting the convective heat or mass transfer coefficients.

scholarly journals Coupled Dynamics of Cable-Harnessed Structures: Experimental Validation

2019 ◽  
Vol 141 (6) ◽  
Author(s):  
Karthik Yerrapragada ◽  
Armaghan Salehian
Keyword(s):  
Experimental Study ◽  
Partial Differential Equations ◽  
Frequency Response ◽  
Experimental Validation ◽  
Response Functions ◽  
Beam Structure ◽  
Coupled Dynamics ◽  
Coupled Partial Differential Equations ◽  
Offset Distance ◽  
Good Agreement

The experimental study and model validations for the coupled dynamics of a cable-harnessed beam structure are presented. The system under consideration consists of multiple pretensioned cables attached along the length of the host beam structure positioned at an offset distance from the beam centerline. Analytical model presented by the coupled partial differential equations (PDEs) for various coordinates of vibrations is found, and the displacement frequency response functions (FRFs) obtained for both Euler–Bernoulli and Timoshenko-based models are compared to those from the experiments for validation. The results are shown to be in very good agreement with the experiments.

Theoretical and Experimental Study on Large Amplitude Vibrations of Clamped Viscoelastic Plates

2016 ◽  
Author(s):  
Prabakaran Balasubramanian ◽  
Giovanni Ferrari ◽  
Zenon J. Guzman N. del Prado ◽  
Marco Amabili
Keyword(s):  
Boundary Condition ◽  
Experimental Study ◽  
Frequency Response ◽  
Large Amplitude ◽  
Continuation Method ◽  
Mode Shapes ◽  
Harmonic Load ◽  
Response Curves ◽  
Voigt Model ◽  
Large Amplitude Vibrations

In this paper, the large amplitude vibrations of clamped-clamped thin viscoelastic rectangular plates due to a concentrated transversal harmonic load are investigated both theoretically and experimentally. Clamped boundary condition on all edges and von Kármán nonlinear strain-displacement relationships are considered while rotary inertia, geometric imperfections, and shear deformation are neglected. In the theoretical study, the viscoelastic behaviour of the material is modelled using the Kelvin-Voigt model. In-plane loads applied during the assembly of the plate are taken into account and clamped boundary conditions are modelled using artificial rotational springs. The nonlinear ordinary differential equations for the considered Kelvin-Voigt model are obtained using the generalized energy approach. These equations contain quadratic and cubic nonlinear viscoelasticity terms in addition to quadratic and cubic stiffness terms. Non-dimensionalization of variables is carried out and each second order equation is converted into two first order equations. The resulting system of equations is solved using AUTO (software based on the arclength continuation method that allows bifurcation analysis), to get the frequency-response curves at various force levels. Moreover numerical time integration of equations was also performed using the fourth-order Runge-Kutta method to understand the time response of the structure. In the experimental study, two rubber plates with different material and thicknesses were considered; a silicone plate with 0.0015 m thickness and a neoprene plate with 0.003 m thickness. The plates were fixed on a heavy rectangular metal frame thereby ensuring the clamped boundary condition on all edges. Linear experimental modal analysis was carried out as a first step to estimate the mode shapes and natural frequencies. In the second step, the nonlinear vibration response of the plate around its first resonance was measured at various harmonic force levels. At each force level, the amplitude of the harmonic excitation was kept constant by LMS Data Acquisition System and Test.Lab Stepped Sine software module while slowly varying the frequency of excitation to get the frequency-response curves. Laser Doppler Vibrometry was used to measure the response from the plate as it eliminates the possible mass loading effect introduced by any contact type sensors. A maximum amplitude of more than three times the thickness of the plate was achieved. The nonlinear response curves showed a typical hardening type nonlinearity along with sudden jumps as expected for plates. Experimental frequency-response curves were compared with theoretical results and a good agreement was found. The influence of nonlinear viscoelastic damping terms was clearly noticed on the response curves of the plate. The retardation time, measured in seconds decreases with increasing excitation force and larger amplitude vibrations.

Experimental Study on CH4 / Air Diffusion Combustion on the Upper Surface of Porous Media Packed Beds

2012 ◽  
Vol 516-517 ◽  
pp. 62-65 ◽  
Author(s):  
Xin Zhang Huang ◽  
Xiu Li Zhang ◽  
Jun Rui Shi ◽  
Zhi Jia Xue ◽  
You Ning Xu ◽  
...  
Keyword(s):  
Experimental Study ◽  
Porous Media ◽  
Packed Bed ◽  
Flame Height ◽  
Diffusion Combustion ◽  
Packed Beds ◽  
Flame Shape ◽  
Air Diffusion

This paper experimentally study on CH4/ air co-flow diffusion combustion on the upper surface of porous media packed beds. The flame height and flame shape were reconstructed from the upper and the side of the combustor. The influence of the height of the packed bed on the flame height and flame shape is reported. It is shown that the flame height decreases rapidly and the circular diameter increases rapidly with increase the height of the packed beds.

Hydrodynamics of liquid flow in packed beds: an experimental study using electrochemical shear rate sensors

1994 ◽  
Vol 49 (6) ◽  
pp. 889-900 ◽  
Author(s):  
S. Rode ◽  
N. Midoux ◽  
M.A. Latifi ◽  
A. Storck ◽  
E. Saatdjian
Keyword(s):  
Experimental Study ◽  
Shear Rate ◽  
Liquid Flow ◽  
Packed Beds
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