Control of Mass Flow-Rate of Viscoelastic Fluids Through Time-Periodic Electro-Osmotic Flows in a Microchannel

2021 ◽  
Author(s):  
Sayantan Dawn ◽  
Sandip Sarkar
Keyword(s):  
Electric Field ◽  
Mass Flow Rate ◽  
Double Layer ◽  
Viscoelastic Fluid ◽  
Mass Flow ◽  
Flow Rate ◽  
Electric Double Layer ◽  
Viscoelastic Fluids ◽  
Shear Thinning ◽  
Time Periodic

Abstract In the present research, we address the implications of the pulsating electric field on controlling mass flow-rate characteristics for the time-periodic electro-osmotic flow of a viscoelastic fluid through a microchannel. Going beyond the Debye-Hückel linearization for the potential distribution inside the Electric Double Layer, the Phan-Thien-Tanner constitutive model is employed to describe the viscoelastic behaviour of the fluid. The analytical/semi-analytical expressions for the velocity distribution corresponding to a steady basic part, and a transient perturbed part are obtained by considering periodic pulsations in the applied electrical field. Our results based on sinusoidal pulsations reveal that enhanced shear thinning characteristics of the viscoelastic fluids show higher amplitude of pulsations with the oscillations in the velocity gradients primarily contrived within the Electric Double Layer region. The amplitude of mass flow rates increases with increasing the viscoelastic parameter , whereas, the phase lag displays a reverse trend. The analysis for an inverse problem is extended where the required magnitude of electric field pulsations for a target mass flow rate in the form of sinusoidal pulsations. It is found that with increasing shear-thinning characteristics of the viscoelastic fluid, there is a progressive reduction in the required electric field strength to maintain an aimed mass flow rate. Besides, required electric fields for controlled mass flow with triangular and trapezoidal pulsations are also determined.

Performance Evaluation of Concentrated Photovoltaic System Using a Microchannel Heat Sink

2016 ◽  
Author(s):  
Ali Radwan ◽  
Mahmoud Ahmed ◽  
Shinichi Ookawara
Keyword(s):  
Solar Cell ◽  
Mass Flow Rate ◽  
Double Layer ◽  
Mass Flow ◽  
Flow Rate ◽  
Heat Sink ◽  
Single Layer ◽  
Microchannel Heat Sink ◽  
Pumping Power ◽  
Cell Temperature

The high incident heat flux on the concentrated photovoltaic (CPV) system causes a significant increase in the cell temperature and thus reduces the system efficiency. Therefore, using an efficient cooling technique is of great importance for those systems. In the present study, a new technology for concentrated photovoltaic systems is introduced using a truncated-double layer microchannel heat sink. A comprehensive three-dimensional thermo-fluid model for the photovoltaic layers integrated with a microchannel heat sink was developed. The proposed model was simulated numerically to estimate the solar cell temperature, temperature uniformity, cooling system pumping power, electrical efficiency and thermal efficiency of the CPV system. The numerical results were validated with the available experimental, analytical and numerical results in the literature. In the designed heat sink, various design parameters are investigated such as the truncation length, cooling mass flow rate, concentration ratio, and converging width ratio of the flow channel. Results indicate that increasing the truncated length leads to an increase of solar cell temperature at a constant coolant mass flow rate. The cell temperature varies between 80.1°C and 146.5°C as the truncation length ratio increases from 0 (i.e. single layer microchannel) to 1 respectively at a concentration ratio (CR) of 40 and a cooling mass flow rate (ṁ) of 26.6 g/min. Using the double layer microchannel reduces the consumed pumping power at the same total mass flow rate compared to the single layer microchannel. The Double layer configuration with a truncation length ratio (l/lsc) equal to unity achieves a lower pumping power and solar cell temperature uniformity in comparison to the single layer microchannel.

scholarly journals Effects of permeability and electric field on nonlinear Oberbeck Electro-convection in a vertical poorly conducting fluid saturated porous channel

2018 ◽  
Vol 12 (1) ◽  
pp. 1-12
Author(s):  
N. Rudraiah ◽  
B. S. Shashikala
Keyword(s):  
Electric Field ◽  
Skin Friction ◽  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Temperature Difference ◽  
Analytical Solutions ◽  
Numerical Solutions ◽  
Potential Difference ◽  
Conducting Fluid

The effects of permeability on nonlinear Oberbeck Electro-convection in a poorly conducting fluid saturated porous medium in a vertical channel, when the walls are held at different temperatures with temperature difference perpendicular to gravity, is studied using the modified Navier stokes equation in the presence of both induced and an applied electric field. Both analytical and numerical solutions for the non-linear coupled equations governing the motion are obtained and found that analytical solutions agree well with numerical solutions for values of the buoyancy parameter N <1. It is shown that OBEC can be controlled by maintaining the temperature difference either in the same direction or opposing the potential difference with a suitable value of electric number W. The effect of W on velocity, temperature, rate of heat transfer, skin friction and mass flow rate are computed and the results are depicted graphically. We found that the analytical solutions for velocity and temperature distributions are in close agreement with those obtained from the numerical method for small values of N. We also found that an increase in W accelerates the flow and hence increases linearly the skin friction and mass flow rate. Further, the velocity and temperature have the same behavior for different values of porous parameter when the temperature difference and the potential difference are in the same or in the opposite directions.Kathmandu University Journal of Science, Engineering and Technology Vol. 12, No. I, June, 2016

The standard unit mass flow rate of gas-liquid mixtures

2020 ◽  
pp. 13-16
Author(s):  
V.N. Petrov ◽  
◽  
V.F. Sopin ◽  
L.A. Akhmetzyanova ◽  
Ya.S. Petrova ◽  
...  
Keyword(s):  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Liquid Mixtures ◽  
Unit Mass ◽  
Standard Unit

Prediction of Leakage Mass Flow Rate Through Gas Springs

1987 ◽  
Author(s):  
Roberto Bruno Bossio ◽  
Vincenzo Naso ◽  
Marian Cichy ◽  
Boleslaw Pleszewski
Keyword(s):  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate
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