Header, heat exchanger, and air-conditioning apparatus

Patent metadata

Field	Value
Publication number	US-2019234626-A1
Application number	US-201616319721-A
Country	US
Kind code	A1
Filing date	Sep 12, 2016
Priority date	Sep 12, 2016
Publication date	Aug 1, 2019
Grant date	—

Abstract

A header includes a plurality of branch tubes and a header manifold. If refrigerant flowing into the header manifold forms a pattern of annular flow or churn flow, tips of the branch tubes inserted into the header manifold pass through a liquid-phase portion having a thickness δ [m] and reach a gas-phase portion. The thickness δ [m] of the liquid-phase portion is defined as δ=G×(1−x)×D/(4ρL×ULS), where G is a flow speed [kg/(m2s)] of the refrigerant, x is a quality of the refrigerant, D is an inside diameter [m] of the header manifold, ρL is a liquid density [kg/m3] of the refrigerant, ULS is a reference apparent liquid speed [m/s] that is a maximum value within a range of variation in an apparent gas speed of the refrigerant flowing into a flow space of the header manifold. The reference apparent liquid speed ULS [m/s] is defined as G(1−x)/ρL.

First claim

1 : A header comprising:
a plurality of branch tubes; and a header manifold having a flow space that communicates with the plurality of branch tubes and in which gas-liquid two-phase refrigerant flows upward and is discharged into the plurality of branch tubes, wherein if the refrigerant flowing into the header manifold forms a pattern of annular flow or churn flow, tips of the branch tubes inserted into the header manifold are configured to pass through a liquid-phase portion having a thickness δ [m] and reach a gas-phase portion, wherein the thickness δ [m] of the liquid-phase portion is defined as δ=G×(1−x)×D/(4ρ L ×U LS ), where G is a flow speed [kg/(m 2 s)] of the refrigerant, x is a quality of the refrigerant, D is an inside diameter [m] of the header manifold, ρ L is a liquid density [kg/m 3 ] of the refrigerant, U LS is a reference apparent liquid speed [m/s] that is a maximum value within a range of variation in an apparent gas speed of the refrigerant flowing into the flow space of the header manifold, the reference apparent liquid speed U LS [m/s] being defined as G(1−x)/ρ L .

2 : The header of claim 1 ,
wherein a reference apparent gas speed U GS [m/s] that is a maximum value within a range of variation in an apparent gas speed of the refrigerant flowing into the flow space of the header manifold satisfies a condition U GS ≥α×L×(g×D) 0.5 /(40.6×D)−0.22α×(g×D) 0.5 , where α is a void fraction of the refrigerant, L is an entrance length [m], g is a gravitational acceleration [m/s 2 ], and D is the inside diameter [m] of the header manifold, and wherein the void fraction α of the refrigerant is defined as x/[x+(ρ G /ρ L )×(1−x)], where x is the quality of the refrigerant, ρ G is a gas density [kg/m 3 ] of the refrigerant, and ρ L is the liquid density [kg/m 3 ] of the refrigerant.

3 : The header of claim 2 , wherein the reference apparent gas speed U GS [m/s] that is the maximum value within the range of variation in the apparent gas speed of the refrigerant flowing into the flow space of the header manifold satisfies a condition U GS ≥3.1/(ρ G 0.5 )×[σ×g×(ρ L −ρ G )] 0.25 , where ρ G is the gas density [kg/m 3 ] of the refrigerant, σ is a surface tension [N/m] of the refrigerant, g is the gravitational acceleration [m/s 2 ], and ρ L is the liquid density [kg/m 3 ] of the refrigerant.

4 : A header comprising:
a plurality of branch tubes; and a header manifold having a flow space that communicates with the plurality of branch tubes and in which gas-liquid two-phase refrigerant flows upward and is discharged into the plurality of branch tubes, wherein, when a center position of the flow space of the header manifold in a horizontal plane is defined as 0% and a position of a wall surface of the flow space of the header manifold in the horizontal plane is defined as 100% on either side, a tip of each of the branch tubes inserted into the header manifold is positioned in an area within 50% on either side, wherein a reference apparent gas speed U GS [m/s] that is a maximum value within a range of variation in an apparent gas speed of the refrigerant flowing into the flow space of the header manifold satisfies a condition U GS ≥α×L×(g×D) 0.5 /(40.6×D)−0.22α×(g×D) 0.5 , where α is a void fraction of the refrigerant, L is an entrance length [m], g is a gravitational acceleration [m/s 2 ], and D is an inside diameter [m] of the header manifold, and wherein the void fraction a of the refrigerant is defined as x/[x+(ρ G /ρ L )×(1−x)], where x is a quality of the refrigerant, ρ G is a gas density [kg/m 3 ] of the refrigerant, and ρ L is a liquid density [kg/m 3 ] of the refrigerant.

5 : The header of claim 4 , wherein the reference apparent gas speed U GS [m/s] that is the maximum value within the range of variation in the apparent gas speed of the refrigerant flowing into the flow space of the header manifold satisfies a condition U GS ≥3.1/(ρ G 0.5 )×[σ×g×(ρ L −ρ G )] 0.25 , where ρ G is the gas density [kg/m 3 ] of the refrigerant, σ is a surface tension [N/m] of the refrigerant, g is the gravitational acceleration [m/s 2 ], and ρ L is the liquid density [kg/m 3 ] of the refrigerant.

6 : The header of claim 1 , wherein, when a center position of the flow space of the header manifold in a horizontal plane is defined as 0%; a position of a wall surface of the flow space of the header manifold in the horizontal plane is defined as 100% on either side; a direction of insertion of each of the plurality of branch tubes in the horizontal plane is defined as an X direction; and a width direction of each of the plurality of branch tubes that is orthogonal to the X direction in the horizontal plane is defined as a Y direction, tips of all of the plurality of branch tubes are positioned in an area within 50% on either side in the X direction; and center axes of all of the plurality of branch tubes are positioned in an area within 50% on either side in the Y direction.

7 : The header of claim 6 , wherein the tips of all of the plurality of branch tubes are positioned in an area within 25% on either side in the X direction, and the center axes of all of the plurality of branch tubes are positioned in an area within 25% on either side in the Y direction.

8 : The header of claim 7 , wherein the tips of all of the plurality of branch tubes are positioned at 0% in the X direction, and the center axes of all of the plurality of branch tubes are positioned at 0% in the Y direction.

9 : The header of claim 1 , wherein, when a flow rate [kg/h] of the refrigerant is M R ; the quality of the refrigerant flowing into the header manifold in a rated heating operation is x; and an effective passage-section area [m 2 ] of the header manifold is A, the quality x of the refrigerant flowing into the header manifold satisfies a condition 0.05≤x≤0.30, and a parameter (M R ×x)/(31.6×A) concerning a thickness of a liquid film formed of the refrigerant falls within a range 0.004×10 6 ≤(M R ×x)/(31.6×A)≤0.120×10 6 .

10 : The header of claim 9 , wherein, when the flow rate [kg/h] of the refrigerant is M R ; the quality of the refrigerant flowing into the header manifold in the rated heating operation is x; and the effective passage-section area [m 2 ] of the header manifold is A, the quality x of the refrigerant flowing into the header manifold satisfies the condition 0.05≤x≤0.30, and the parameter (M R ×x)/(31.6×A) concerning the thickness of the liquid film formed of the refrigerant falls within a range 0.010×10 6 ≤(M R ×x)/(31.6×A)≤0.120×10 6 .

11 : The header of claim 1 , wherein, when the flow rate [kg/h] of the refrigerant is M R and the quality of the refrigerant flowing into the header manifold in the rated heating operation is x, the quality x of the refrigerant flowing into the header manifold satisfies the condition 0.05≤x≤0.30, the inside diameter D [m] of the header manifold falls within a range 0.010≤D≤0.018, and a parameter (M R ×x)/31.6 concerning the thickness of the liquid film formed of the refrigerant falls within a range 0.427≤(M R ×x)/31.6≤5.700.

12 : The header of claim 1 , wherein, when the quality of the refrigerant flowing into the header manifold in the rated heating operation is x and the effective passage-section area [m 2 ] of the header manifold is A, the quality x of the refrigerant flowing into the header manifold satisfies the condition 0.05≤x≤0.30, the inside diameter D [m] of the header manifold falls within the range 0.010≤D≤0.018, and a parameter x/(31.6×A) concerning the thickness of the liquid film formed of the refrigerant falls within a range 1.4×10≤x/(31.6×A)≤8.7×10.

13 : The header of claim 1 ,
wherein, when the quality of the r

Assignees

• Mitsubishi Electric Corp

Inventors

• Onaka Yoji
• Matsumoto Takashi
• Miyawaki Kosuke
• Okano Hiroyuki
• Koike Takanori
• Hatomura Takeshi
• Morimoto Osamu

Classifications

• F24F1/14 Primary

  Heat exchangers specially adapted for separate outdoor units · CPC title

• F25B1/005

  of the single unit type (F25B1/10 takes precedence) · CPC title

• F28F9/02

  Header boxes; End plates · CPC title

• F25B39/02

  Evaporators · CPC title

• F28F9/026

  with static flow control means, e.g. with means for uniformly distributing heat exchange media into conduits · CPC title