Suppressing turbulence and enhancing liquid suspension flow in pipelines with electrorheology

Flows through pipes, such as crude oil through pipelines, are the most common and important method of transportation of fluids. To enhance the flow output along the pipeline requires reducing viscosity and suppressing turbulence simultaneously and effectively. Unfortunately, no method is currently available to accomplish both goals simultaneously. Here we show that electrorheology provides an efficient solution. When a strong electric field is applied along the flow direction in a small section of pipeline, the field polarizes and aggregates the particles suspended inside the base liquid into short chains along the flow direction. Such aggregation breaks the rotational symmetry and makes the fluid viscosity anisotropic. In the directions perpendicular to the flow, the viscosity is substantially increased, effectively suppressing the turbulence. Along the flow direction, the viscosity is significantly reduced; thus the flow along the pipeline is enhanced. Recent field tests with a crude oil pipeline fully confirm the theoretical results.

Figure 1

As the liquid suspension flow passes a strong local electric field, the suspended particles are aggregated into short chains along the field direction.

Figure 2

Small-angle neutron scattering has confirmed the aggregation. With no electric field, the scattering is isotropic and sparse, indicating the particles are randomly distributed in the oil (left). Under an electric field of $250\mathrm{V}/\mathrm{mm}$ (middle), the scattering reveals short chains of particles aggregated along the field direction. When $E=400\mathrm{V}/\mathrm{mm}$, the short chain has a prolate spheroid shape (right).

Figure 3

The electric field makes the viscosity along the flow direction much lower than the original viscosity, while it raises the viscosity perpendicular to the flow much higher than the original viscosity.

Figure 4

The AOT device is placed downstream next to the pump.

Figure 5

After the AOT device was turned on, there was less pressure loss. When the loop was filled with all treated crude oil, the pressure loss was down 40%. After the device was turned off, the pressure loss returned to the original value as the untreated crude oil pushed the treated crude oil away.

Figure 6

The electric-field-treated oil flow has pump pressure linearly proportional to the flow rate, indicating the flow remains laminar as the Reynolds number reaches 6348. The untreated oil has pump pressure increasing much faster than the linear relation with the flow rate, indicting the flow becomes turbulent when the Reynolds number >2300.

Figure 7

Outside the electric field, the viscosity of treated crude oil goes up slowly after the treatment.

Figure 8

During the test, the treated crude oil kept its reduced viscosity for 11 h after the AOT device was shut off.