INDUCERS FOR CRYOGENIC PUMPS AND RELATED SYSTEMS AND METHODS
An inducer may include a hub having an outer lateral surface extending from a leading end to a trailing end, the outer lateral surface having a leading surface section having a first cylindrical shape, an intermediate surface section having a frustoconical shape, and a trailing surface section having a second cylindrical shape. The inducer may include main blades extending circumferentially along a first helical path over the leading surface section, the intermediate surface section, and the trailing surface section, the first helical path having an increasing helix angle. The inducer may additionally include splitter blades, each of the splitter blades located circumferentially between two of the main blades, respectively.
1 . An inducer for a cryogenic pump, the inducer comprising:
a hub having an outer lateral surface extending from a leading end to a trailing end, the outer lateral surface having a leading surface section having a first cylindrical shape, an intermediate surface section having a frustoconical shape, and a trailing surface section having a second cylindrical shape;
main blades extending radially from the outer lateral surface of the hub toward an outer diameter of the inducer and extending circumferentially along a first helical path over the leading surface section, the intermediate surface section, and the trailing surface section, the first helical path having an increasing helix angle from the leading surface section to the trailing surface section defining a main blade angle of the main blades; and
splitter blades extending radially from the outer lateral surface of the hub toward the outer diameter of the inducer and extending circumferentially along a second helical path over at least the intermediate surface section and the trailing surface section of the outer lateral surface of the hub, the second helical path having an increasing helix angle from the leading surface section to the trailing surface section defining a splitter blade angle of the splitter blades, each of the splitter blades located between two of the main blades, respectively.
2 . The inducer of claim 1 , wherein a diameter of the trailing surface section of the hub is at least about 75% of the outer diameter of the inducer.
3 . The inducer of claim 2 , wherein the diameter of the trailing surface section of the hub is about 78% of the outer diameter of the inducer.
4 . The inducer of claim 2 , wherein a diameter of the leading surface section of the hub is less than about 33% of the outer diameter of the inducer.
5 . The inducer of claim 4 , wherein the diameter of the leading surface section of the hub is about 30% of the outer diameter of the inducer.
6 . The inducer of claim 1 , wherein each of the main blades have a swept leading edge defined by a gradually increasing radial blade length over a sweep angle of at least 40 degrees from a leading tip, located at the leading surface section of the hub, to a trailing end, located at the outer diameter of the inducer.
7 . The inducer of claim 1 , wherein a leading edge of each splitter blade is positioned relatively closer to a circumferentially trailing main blade than a circumferentially leading main blade.
8 . The inducer of claim 1 , wherein the leading surface section of the hub is greater than 5% of an axial length of the inducer and the trailing surface section of the hub is greater than 5% of the axial length of the inducer.
9 . The inducer of claim 1 , wherein each of the main blades and each of the splitter blades comprise an arcuate outer lateral surface defining the outer diameter of the inducer.
10 . The inducer of claim 9 , wherein the arcuate outer lateral surface of one or more of the main blades has a wrap angle of about 180 degrees.
11 . The inducer of claim 1 , wherein the main blade angle of one or more of the main blades at the outer diameter of the inducer is smaller than the main blade angle at the outer lateral surface of the hub corresponding to a same axial location.
12 . The inducer of claim 11 , wherein the main blade angle of one or more of the main blades at a leading edge location at the outer lateral surface of the hub is less than about 25 degrees.
13 . The inducer of claim 12 , wherein the main blade angle of one or more of the main blades at a trailing edge location at the outer lateral surface of the hub is greater than about 27 degrees.
14 . The inducer of claim 13 , wherein the main blade angle of one or more of the main blades at the leading edge location at the outer diameter of the inducer is less than about 8.5 degrees.
15 . The inducer of claim 14 , wherein the main blade angle of one or more of the main blades at the trailing edge location at the outer diameter of the inducer is greater than about 20 degrees.
16 . A pump for pumping a cryogenic fluid, the pump comprising:
a fluid inlet and a fluid outlet;
a motor;
a pump stage;
an inducer located between the fluid inlet and the pump stage, the inducer comprising:
a hub having an outer lateral surface extending from a leading end to a trailing end, the outer lateral surface having a leading surface section having a first cylindrical shape, an intermediate surface section having a frustoconical shape, and a trailing surface section having a second cylindrical shape;
main blades extending radially from the outer lateral surface of the hub to an outer diameter of the inducer and extending circumferentially along a first helical path from the leading surface section to the trailing surface section, the main blades having an increasing helix angle from the leading surface section to the trailing surface section; and
splitter blades extending radially from the outer lateral surface of the hub to the outer diameter of the inducer and extending circumferentially along a second helical path from the intermediate surface section to the trailing surface section of the outer lateral surface of the hub, the splitter blades having an increasing helix angle from the leading surface section to the trailing surface section; and
a drive shaft coupling the motor to the pump stage and the inducer.
17 . The pump of claim 16 , further comprising an inducer guide vane located between the inducer and the pump stage.
18 . A method of inducing flow into a cryogenic pump, the method comprising rotating an inducer to draw fluid through a fluid inlet with the inducer and direct the fluid into an inducer guide vane to provide fluid to a first pump stage of the cryogenic pump at a pressure greater than about 100 feet of head higher than at the fluid inlet and with greater than 3 degrees Kelvin subcooling relative to a fluid temperature at the fluid inlet.
19 . The method of claim 18 , further comprising providing fluid to the first pump stage of the cryogenic pump at a pressure greater than about 140 feet of head higher than at the fluid inlet and with greater than 5 degrees Kelvin subcooling relative to the fluid temperature at the fluid inlet.
20 . The method of claim 18 , further comprising recondensing fluid having a vapor fraction over 18% at the fluid inlet and delivering the fluid in a subcooled liquid state to the first pump stage.