EXPANSION, FLOW THROUGH AND PRESSURE DROP

The flow of a liquid through a tube deformed by a piezoelectric cell under a harmonic law is studied in this paper. Linear deformations are compared for the Dirichlet and Neumann boundary conditions on the contact surface of the tube and piezoelectric element. The flow of fluid through a deformed channel for two flow regimes is investigated: in a tube with one closed end due to deformation of the tube; for a tube with two open ends due to deformation of the tube and the differential pressure applied to the channel. The flow rate of the liquid is calculated as a function of the frequency of the deformations, the pressure drop and the physical parameters of the liquid.

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Two-phase countercurrent flow through a bed of packing. VII. Pressure drop at flooding and critical flow rates of both phases in packed bed of spheres

Collection of Czechoslovak Chemical Communications ◽

10.1135/cccc19721666 ◽

1972 ◽

Vol 37 (5) ◽

pp. 1666-1670

Author(s):

V. Kolář ◽

Z. Brož

Keyword(s):

Pressure Drop ◽

Packed Bed ◽

Critical Flow ◽

Countercurrent Flow ◽

Two Phase ◽

Flow Rates ◽

Flow Through

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Observation of Pressure Drop Behavior in an Operating Fuel Cell Stack

ASME 2005 Power Conference ◽

10.1115/pwr2005-50074 ◽

2005 ◽

Author(s):

Frano Barbir ◽

Haluk Gorgun ◽

Xinting Wang

Keyword(s):

Fuel Cell ◽

Pressure Drop ◽

Proton Exchange Membrane ◽

Proton Exchange ◽

Cathode Side ◽

Fuel Cell Stack ◽

Flow Through ◽

Drying Conditions ◽

Exchange Membrane ◽

The Relationship

Pressure drop on the cathode side of a PEM (Proton Exchange Membrane) fuel cell stack has been studied and used as a diagnostic tool. Since the Reynolds number at the beginning of the flow field channel was <250, the flow through the channel is laminar, and the relationship between the pressure drop and the flow rate is linear. Some departure from linearity was observed when water was either introduced in the stack or produced inside the stack in the electrochemical reaction. By monitoring the pressure drop in conjunction with the cell resistance in an operational fuel cell stack, it was possible to diagnose either flooding or drying conditions inside the stack.

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Heat Enhancement Effectiveness Using Multiple Twisted Tape in Rectangular Channels

Fluids ◽

10.3390/fluids6050188 ◽

2021 ◽

Vol 6 (5) ◽

pp. 188

Author(s):

M. Ziad Saghir ◽

Ayman Bayomy ◽

Md Abdur Rahman

Keyword(s):

Pressure Drop ◽

Heat Removal ◽

Energy System ◽

Twisted Tape ◽

Heat Exchanger Design ◽

Twisted Tapes ◽

Rectangular Channels ◽

Flow Through ◽

The Subject ◽

Energy Coefficient

Heat enhancement and heat removal have been the subject of considerable research in the energy system field. Flow-through channels and pipes have received much attention from engineers involved in heat exchanger design and construction. The use of insert tape is one of many ways to mix fluids, even in a laminar flow regime. The present study focused on the use of different twisted tapes with different pitch-to-pitch distances and lengths to determine the optimum design for the best possible performance energy coefficient. The results revealed that twisted tape of one revolution represented the optimal design configuration and provided the largest Nusselt number. The length of the tape played a major role in the pressure drop. The results revealed that the insertion of a shorter twisted tape can create mixing while minimizing the changes in the pressure drop. In particular, the best performance evaluation criterion is found for a short tape located towards the exit of the channel. The highest performance energy coefficient was obtained for the half-twisted tape for a Reynolds number varying between 200 and 600.

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