NOZZLE, DEVICE, AND METHOD FOR HIGH-SPEED GENERATION OF UNIFORM NANOPARTICLES

• US 20170072537A1
• Filed: 11/02/2016
• Published: 03/16/2017
• Est. Priority Date: 06/12/2015
• Status: Active Grant

• Current Assignee: Postech Academy-Industry Foundation
• Original Assignee: Postech Academy-Industry Foundation
• Inventors: LEE, Jin Won, KIM, In Ho
• Granted Patent: US 10,081,091 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: B24C 1/003 using material which dissolves or changes phase after the treatment, e.g. ice, CO2
• CPC Class Codes: B24C 5/04 Nozzles therefor nozzles in general B05B

Abstract

A nozzle, a device, and a method for high-speed generation of uniform nanoparticles allow a particle generation gas formed of carbon dioxide to pass through the nozzle, thereby forming uniform nanoparticles at high speed. An orifice that adjusts an opening and closing cross-sectional area of a throat of the nozzle is provided to cause uniform nuclei generation without an additional cooling device, a dilating portion that has a cross-sectional area and a dilation angle increasing toward an outlet side of the nozzle is provided to grow the nuclei through a first dilation portion (having a relatively gradual dilation angle) and thus cause particle generation, and the generated particles are accelerated through a second dilating portion that has a steeper dilation angle than the first dilating portion.

Claims

1. A method of generating high-speed uniform nanoparticles by passing a particle generation gas formed of carbon dioxide through a nozzle, the method comprising:

a nucleus generation step of generating nuclei as the particle generation gas rapidly expands while passing through an orifice provided in a nozzle throat of the nozzle;

a particle generation step of generating sublimation particles as growth of nuclei is accomplished while the particle generation gas passes through a first dilating portion extended from an outlet of the nozzle throat and having a dilation angle of 0°

to 30°

, after performing the nucleus generation step; and

a particle acceleration step of offsetting growth of a boundary layer and increasing speed of injecting the sublimation particles while the particle generation gas passes through the second dilating portion extended from an outlet of the first dilating portion and having an average dilation angle increased by 10°

to 45°

compared with the dilation angle of the first dilating portion, after performing the particle generation step.

2. The method according to claim 1, further comprising a pressure control step of adjusting pressure of the particle generation gas as a prior step of the nucleus generation step.

3. The method according to claim 2, wherein the pressure of the particle generation gas passing through the pressure control step is controlled to 5 to 60 bar to flow the particle generation gas into the nozzle.

4. The method according to claim 1, further comprising:

a mixing step of forming a mixture gas by mixing the particle generation gas and a carrier gas; and

a pressure control step of adjusting pressure of the mixture gas passing through the mixing step,

as prior steps of the nucleus generation step.

5. The method according to claim 4, wherein the carrier gas is formed of nitrogen or helium, and the pressure of the mixture gas passing through the pressure control step is controlled to 5 to 120 bar to flow the mixture gas into the nozzle.

6. The method according to claim 1, further including, after performing the particle acceleration step, a flow control step of forming a high-speed core of the sublimation particles outside the nozzle as the particle generation gas passes through a third dilating portion extended from an outlet of the second dilating portion and having a dilation angle increased by 10°

to 45°

compared with the average dilation angle of the second dilating portion and lower than 90°

in maximum.