Heat transfer tube including a groove portion having a spiral shape extending continuously and a rib portion extending continuously and protruding inward by the groove portion
A heat transfer tube for a boiler, an interior of the heat transfer tube having a supercritical pressure and being configured to have a heating medium flow therethrough, includes: a groove portion defined on an inner circumferential surface and having a spiral shape extending continuously toward a tube axis direction; and a rib portion extending continuously and protruding inward in a radial direction by the groove portion of the spiral shape. In a cross section taken along the tube axis direction, a width of the groove portion in the tube axis direction is defined as Wg, a height of the rib portion in the radial direction is defined as Hr and a tube outer diameter is defined as D, and the width Wg of the groove portion, the height Hr of the rib portion, and the tube outer diameter D satisfy Wg/(Hr·D)>0.40.
1. A heat transfer tube for a boiler, an interior of the heat transfer tube being configured to have a heating medium flow therethrough, the heat transfer tube comprising:
a groove portion that is defined on an inner circumferential surface and has a spiral shape extending continuously toward a tube axis direction; and
a rib portion that extends continuously and protrudes inward in a radial direction by the groove portion of the spiral shape,
wherein, in a cross section taken along the tube axis direction, a width [mm] of the groove portion in the tube axis direction is defined as Wg, a height [mm] of the rib portion in the radial direction is defined as Hr, and a tube outer diameter [mm] is defined as D,
wherein the width Wg [mm] of the groove portion, the height Hr [mm] of the rib portion, and the tube outer diameter D [mm] satisfy “Wg/(Hr·D)>0.40”,
wherein the interior of the heat transfer tube has a supercritical pressure,
wherein, an interval [mm] of the rib portion in the tube axis direction is defined as Pr, the number of the rib portion in a cross section which is taken perpendicularly to the tube axis direction is defined as Nr, and a wetted perimeter length [mm] of the cross section which is taken perpendicularly to the tube axis direction is defined as L, and
wherein the height Hr [mm] of the rib portion, the interval Pr [mm] of the rib portion, the number of the rib portion Nr and the wetted perimeter length L [mm] satisfy “(Pr·Nr)/Hr>1.25L+55”.
2. The heat transfer tube according to claim 1 ,
wherein, when the boiler is operated at a rated output, an average mass velocity of the heating medium flowing through the interior of the heat transfer tube becomes 1000 to 2000 kg/m 2 s.
3. The heat transfer tube according to claim 1 , wherein, when the boiler is operated at a rated output, an average mass velocity of the heating medium flowing through the interior of the heat transfer tube is equal to or less than 1500 kg/m 2 s.
4. The heat transfer tube according to claim 1 ,
wherein the tube outer diameter D [mm] is “25 mm≤D≤40 mm”.
5. The heat transfer tube according to claim 1 , wherein, a width [mm] of the rib portion in a circumferential direction of the inner circumferential surface is defined as Wr, and
wherein the height Hr [mm] of the rib portion, the interval Pr [mm] of the rib portion, the width Wr [mm] of the rib portion, the number Nr of the rib portion and the wetted perimeter length L [mm] satisfy “(Pr·Nr)/(Hr·Wr)<0.40L+80”.
6. A boiler comprising the heat transfer tube according to claim 1 that is configured as a furnace wall tube that defines a furnace wall of the boiler.
7. A boiler configured to heat the heating medium flowing through the interior of the heat transfer tube according to claim 1 , by heating the heat transfer tube by radiation of flame or high-temperature gas.
8. A steam turbine device comprising:
the boiler according to claim 6 ; and
a steam turbine configured to be operated by steam generated by heating of water as the heating medium which flows through the interior of the heat transfer tube in the boiler.
9. The heat transfer tube according to claim 2 ,
wherein the tube outer diameter D [mm] is “25 mm≤D≤40 mm”.
10. A heat transfer tube for a boiler, an interior of the heat transfer tube being configured to have a heating medium flow therethrough, the heat transfer tube comprising:
a groove portion that is defined on an inner circumferential surface and has a spiral shape extending continuously toward a tube axis direction; and
a rib portion that extends continuously and protrudes inward in a radial direction by the groove portion of the spiral shape,
wherein, a height [mm] of the rib portion in the radial direction is defined as Hr, an interval [mm] of the rib portion in the tube axis direction is defined as Pr, the number of the rib portion in a cross section which is taken perpendicularly to the tube axis direction is defined as Nr, and a wetted perimeter length [mm] of the cross section which is taken perpendicularly to the tube axis direction is defined as L,
wherein the height Hr [mm] of the rib portion, the interval Pr [mm] of the rib portion, the number Nr of the rib portion and the wetted perimeter length L [mm] satisfy “(Pr·Nr)/Hr>1.25L+55”, and
wherein the interior of the heat transfer tube has a supercritical pressure.
11. The heat transfer tube according to claim 10 ,
wherein, when the boiler is operated at a rated output, an average mass velocity of the heating medium flowing through the interior of the heat transfer tube is equal to or less than 1500 kg/m 2 s.
12. The heat transfer tube according to claim 10 , wherein, when the boiler is operated at a rated output, an average mass velocity of the heating medium flowing through the interior of the heat transfer tube becomes 1000 to 2000 kg/m 2 s.
13. The heat transfer tube according to claim 10 , wherein the tube outer diameter D [mm] is “25 mm<D<40 mm”.
14. A heat transfer tube for a boiler, an interior of the heat transfer tube being configured to have a heating medium flow therethrough, the heat transfer tube comprising:
a groove portion that is defined on an inner circumferential surface and has a spiral shape extending continuously toward a tube axis direction; and
a rib portion that extends continuously and protrudes inward in a radial direction by the groove portion of the spiral shape,
wherein, a height [mm] of the rib portion in the radial direction is defined as Hr, an interval [mm] of the rib portion in the tube axis direction is defined as Pr, a width [mm] of the rib portion in a circumferential direction of the inner circumferential surface is defined as Wr, the number of the rib portion in a cross section which is taken perpendicularly to the tube axis direction is defined as Nr, a wetted perimeter length [mm] of the cross section which is taken perpendicularly to the tube axis direction is defined as L, a width [mm] of the groove portion in the tube axis direction of a cross section which is taken along the tube axis direction is defined as Wg, and a tube outer diameter [mm] is defined as D,
wherein the width Wg [mm] of the groove portion, the height Hr [mm] of the rib portion, and the tube outer diameter D [mm] satisfy “Wg/(Hr·D)>0.40”,
wherein the height Hr [mm] of the rib portion, the interval Pr [mm] of the rib portion, the width Wr [mm] of the rib portion, the number Nr of the rib portion and the wetted perimeter length L [mm] satisfy “(Pr·Nr)/(Hr·Wr)>0.40L+9.0” and
wherein the interior of the heat transfer tube has a supercritical pressure.
15. The heat transfer tube according to claim 14 ,
wherein, when the boiler is operated at a rated output, an average mass velocity of the heating medium flowing through the interior of the heat transfer tube becomes 1000 to 2000 kg/m 2 s.
16. The heat transfer tube according to claim 14 ,
wherein, when the boiler is operated at a rated output, an average mass velocity of the heating medium flowing through the interior of the heat transfer tube is equal to or less than 1500 kg/m 2 s.
17. The heat transfer tube according to claim 15 ,
wherein the tube outer diameter D [mm] is “25 mm≤D≤35 mm”.