Method and apparatus for energy conversion using microfluidic channel array with hierarchical structure

Patent metadata

Field	Value
Publication number	US-10439519-B2
Application number	US-201715803708-A
Country	US
Kind code	B2
Filing date	Nov 3, 2017
Priority date	Oct 13, 2017
Publication date	Oct 8, 2019
Grant date	Oct 8, 2019

Abstract

Disclosed herein is a method and an apparatus using microfluidic channel array for converting mechanical energy into electric energy by streaming potential and streaming current caused when the electrolyte liquid flows in a charged surface due to a pressure drop. The present invention relates to a method and an apparatus for designing channels with hierarchical structure in which a primary multi-channel is provided by radially arranging one or more unit channels, and each of the unit channels includes an inflow channel, an outflow channel, and a secondary multi-channel provided by arranging one or more channels in parallel, thereby improving output power and flow stability.

First claim

What is claimed is:

1. An apparatus for energy conversion including microfluidic channels with hierarchical structure, the apparatus comprising:
a primary multi-channel provided by radially arranging one or more unit channels around an inlet port towards an outside channel;
wherein each of the unit channels includes an inflow channel, an outflow channel, and a secondary multi-channel provided by arranging one or more channels vertically in parallel between the inflow channel and the outflow channel,
wherein the apparatus is provided by connecting an upper substrate of a channel array layer including the inlet port, the radial multi-channel, and the outside channel formed thereon to a lower substrate of a water collecting layer including the outside channel and an outlet port formed thereon,
wherein the inflow channel and the outflow channel are provided to take a trapezoidal shape so as to achieve uniform flow distribution and prevent backflow, whereby a width of the inflow channel gradually decreases as the inflow channel travels away from the inlet port, and a width of the outflow channel gradually increases as the outflow channel approaches the outside channel, and
wherein the decreasing rate in the width of the inflow channel is set to cause an inclination angle θ 1 to be 0 to 10 degrees based on a maximum width W bi and a minimum width W bf of the inflow channel, and the increasing rate in the width of the outflow channel is set to cause an inclination angle θ 2 to be 0 to 10 degrees based on a maximum width and a minimum width of the outflow channel.

2. The apparatus for energy conversion of claim 1 , wherein the inclination angle θ 1 of the decreasing rate in the width of the inflow channel and the inclination angle θ 2 of the increasing rate in the width of the outflow channel are the same or different from each other to be symmetric or asymmetric.

3. The apparatus for energy conversion of claim 1 ,
wherein the width of the inflow channel and the width of the outflow channel are set to be 10 μm to 100 μm at a midpoint (L u /2) in the inflow channel and the outflow channel, and
a width W n of each channel forming the secondary multi-channel is 1/50 to 1/10 of the width of the inflow channel and the width of the outflow channel.

4. The apparatus for energy conversion of claim 1 ,
wherein the inflow channel, the outflow channel, and the secondary multi-channel have all the same height in a range of 1 to 5 times of the width of the inflow channel, the outflow channel, and the secondary multi-channel, respectively.

5. The apparatus for energy conversion of claim 1 ,
wherein an inter-channel distance d in the secondary multi-channel is 1.2 times or more of a width W n of the channels.

6. The apparatus for energy conversion of claim 1 ,
wherein a length of the unit channel is set to be 500 μm to 1 cm, and the number of the unit channels in the upper substrate having the radial multi-channel formed thereon is 20 to 200.

7. The apparatus for energy conversion of claim 1 ,
wherein the upper substrate and the lower substrate are each provided with the outside channel so that liquid transporting through the unit channel is collected and then discharged.

8. The apparatus for energy conversion of claim 1 , further comprising:
a pair of electrode tubing served as an upper electrode and a lower electrode and inserted into the inlet port and the outlet port, respectively; and
an inlet tubing and an outlet tubing of a non-conductive plastic material connected to the upper electrode and the lower electrode, respectively.

9. The apparatus for energy conversion of claim 1 ,
wherein a streaming potential, a streaming current, or both of the streaming potential and the streaming current are measured simultaneously while liquid is being injected and discharged.

10. The apparatus for energy conversion of claim 1 ,
wherein the apparatus enables a primary enhancement in a streaming current from the primary multi-channel and a secondary enhancement in a streaming current from the secondary multi-channel.

11. The apparatus for energy conversion of claim 1 ,
wherein the primary multi-channel is provided by radially arranging the unit channels at equal intervals and the secondary multi-channel formed in each of the unit channels is provided by arranging one or more channels at equal intervals, thereby achieving stable flow by uniform flow distribution without flowing backward in all the channels.

12. An apparatus for energy conversion including microfluidic channels, the apparatus comprising:
an upper substrate including
an inlet port,
an upper part of an outside channel grooved on the upper substrate around the inlet port, and
one or more primary channels radially arranged around the inlet port on the upper substrate, wherein each of the primary channels includes an inflow channel open to the inlet port, an outflow channel open to the upper part of the outside channel, and multiple secondary channels arranged in parallel between the inflow channel and the outflow channel; and

a lower substrate including
a lower part of the outside channel grooved on the lower substrate, wherein the lower part of the outside channel is configured to form the outside channel along with the upper part of the outside channel, and
an outlet port formed on the lower substrate to communicate with the outside channel;

wherein when the upper substrate and the lower substrate are coupled together, the inlet port is open to a top side of the upper substrate and the outlet port is open to a bottom side of the lower substrate.

13. The apparatus for energy conversion of claim 12 , wherein the inflow channel and the outflow channel have a trapezoidal shape such that a width of the inflow channel gradually decreases as the inflow channel travels away from the inlet port, and a width of the outflow channel gradually increases as the outflow channel approaches the outside channel.

14. The apparatus for energy conversion of claim 13 , wherein the decreasing rate in the width of the inflow channel is set to cause an inclination angle θ 1 to be 0 to 10 degrees based on a maximum width W bi and a minimum width W bf of the inflow channel, and the increasing rate in the width of the outflow channel is set to cause an inclination angle θ 2 to be 0 to 10 degrees based on a maximum width and a minimum width of the outflow channel.

15. The apparatus for energy conversion of claim 13 , wherein the width of the inflow channel and the width of the outflow channel are set to be 10 μm to 100 μm at a midpoint (L u /2) in the inflow channel and the outflow channel, and
a width W n of each channel forming the secondary channels is 1/50 to 1/10 of the width of the inflow channel and the width of the outflow channel.

16. The apparatus for energy conversion of claim 13 , wherein the inflow channel, the outflow channel, and the multiple secondary channels have all the same height in a range of 1 to 5 times of the width of the inflow channel, the outflow channel, and the multiple secondary channels, respectively.

17. The apparatus for energy conversion of claim 12 , further comprising:
an upper electrode and a lower electrode inserted into the inlet port and the outlet port, respectively; and
an inlet tubing and an outlet tubing connected to the upper electrode and the lower electrode, respectively.

Assignees

• Korea Inst Sci & Tech

Inventors

• Chun Myung-Suk
• Chun Byoungjin
• Lee Ji-Young
• Jeon Heesoo

Classifications

• H02N1/08 Primary

  with conductive charge carrier, i.e. capacitor machines · CPC title

• H02N3/00 Primary

  Generators in which thermal or kinetic energy is converted into electrical energy by ionisation of a fluid and removal of the charge therefrom (discharge tubes functioning as thermionic generators H01J45/00) · CPC title

• Y02E60/50

  Fuel cells · CPC title

• H01M14/00 Primary

  Electrochemical current or voltage generators not provided for in groups H01M6/00 - H01M12/00; Manufacture thereof · CPC title

• H01M8/227

  Dialytic cells or batteries; Reverse electrodialysis cells or batteries · CPC title