JPH0270992A - High speed turbopump - Google Patents

Abstract

PURPOSE:To realize characteristics equivalent to those of a general purpose pump having a relatively high volume at a high speed by a method wherein the suction guide bore of a suction guide device is increased to a value higher than the impeller inlet size of an impeller, and the suction guide bore is set to an arbitrary value in a range of from an impeller inlet size to the outer size of the impeller. CONSTITUTION:A suction guide bore (d) of a suction guide device 146 is increased to a value approximately equal to that of an outline d2 of an impeller 144 of an impeller 143. According to the suction guide bore, a pump suction bore D can be also increased. Fluid coming through each enlarged suction port 148 of the suction guide device enters a peripheral flow passage on the outlet side of the suction guide device along a slow curve. But, most of the fluid flows toward an impeller inlet edge 144a of the impeller 143 along a flow passage the sectional area of which is gradually reduced in the direction of rotation of the impeller 143, and a part thereof flows to the impeller from the longitudinal edge 144b side of the impeller 144.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention provides a suction guide device provided on the upstream side of an impeller, which has suction guide vanes that partition a plurality of suction channels finely divided in the circumferential direction. The present invention relates to a high-speed turbo pump having a suction guide device formed such that the cross-sectional area of the suction passage gradually decreases in the direction of rotation of the impeller toward the blade inlet edge of the impeller.

[Conventional technology]

When trying to speed up and downsize turbo pumps, small capacity, high head pumps can be easily manufactured. This is because the head generated is proportional to the square of the impeller outer peripheral speed (therefore, the square of the rotational speed) and the flow rate is proportional to the rotational speed, so it is possible to increase the speed by reducing the outer diameter of the impeller.

An example of such a small-capacity, high-head, high-speed pump with a suction guide device upstream of the impeller is the turbo pump of patent application 63-34070 of the present applicant.

FIG. 8 shows an example in which the suction guide device used in this application is applied to a high-speed turbo pump having an impeller with a relatively large inner/outer diameter ratio and a shorter blade length. The blade inner and outer diameter ratio referred to here is the ratio a of the impeller outer diameter d2 and inner diameter d1.
means l/az. An impeller 43 having a large inner/outer diameter ratio and a relatively short blade length is fixed to the end of the rotating shaft 42 protruding into the pump casing 41.
A polyte casing portion 45 is arranged so as to surround 4. Inside the porute casing part 45, upstream of and adjacent to the blades 44 of the impeller 43, the aforementioned suction guide device 46 is removably mounted, and further upstream of this suction guide device, a suction casing 47 is mounted. It is being A plurality of inlets 48 are arranged on the inlet side of the suction guide device 46, and as can be seen from FIG.
Each inlet hole 49 extending from these inlets in the axial direction or inclined in the direction of rotation of the impeller with respect to the axial direction forms a smooth curve in the circumferential flow path toward the blades 44 of the impeller 43 on the outlet side of the suction guide device. Draw and transition, and each circumferential flow path is
The cross-sectional area thereof is formed so as to gradually decrease in the direction of rotation of the impeller toward the blade inlet edge 44a of the impeller 43. The suction guide diameter d of the suction guide device is approximately equal to the blade inlet diameter d of the impeller, and the pump suction diameter of the suction casing is equal to the suction guide diameter d.

Such a design allows fluid to flow into the impeller blades without abrupt flow direction changes at the impeller blade inlet, significantly reducing losses at the impeller blade inlet. , it becomes possible to increase the speed of the pump. By combining this suction guide device with an impeller having a unique configuration, it is possible to relatively easily obtain a high-head, small-capacity turbo pump with a large downward slope of the pump head characteristic curve.

[Problem to be solved]

However, at present, for example, 100 pumps have the same characteristics as relatively large capacity general-purpose pumps manufactured using conventional design methods.
If we try to achieve a high speed of about 00 r, ρ3m, the natural result is that the faster the speed is, the smaller the outer diameter of the impeller becomes. Accordingly, the blade inlet diameter also becomes smaller. If the suction port diameter of the pump is set to match this impeller inlet diameter, even if the impeller outlet width is widened and the flow rate is designed to be large, the pump flow rate will be determined by this suction port diameter and will be small. This means that only small-flow, high-head pumps like the one above can be designed, making it impossible to increase the speed of general-purpose pumps with relatively large capacities.

Therefore, an object of the present invention is to provide a turbo pump that can achieve characteristics similar to those of a general-purpose pump with a relatively large capacity at high speed.

[Means to solve the problem]

In order to achieve the above object, the present invention makes the suction guide diameter (d) of the suction guide device larger than the blade inlet diameter of the impeller, and extends the suction guide diameter from the blade inlet diameter of the impeller to the blade outer diameter. The above problem can be solved by setting the value to an arbitrary value.

〔Example〕

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be explained below with reference to embodiments.

FIG. 1 shows a longitudinal section of a first embodiment of a high-speed turbo pump 140 according to the present invention. Parts similar to FIGS. 8 and 9 have their reference numerals plus 100.

The suction guide aperture of the conventional suction guide device is equal to the blade inlet diameter d1 of the impeller, but according to the present invention, the suction guide aperture d of the suction guide device 146 is set to
The outer diameter of the blade 144 is increased to nearly dz. Accordingly, the diameter of the pump suction port can be increased as shown.

As can be seen from FIG. 2, which shows the suction guide device 146 from the downstream end, each of the enlarged suction ports 148 of the suction guide device
The more inflowing fluid enters the circumferential flow path on the outlet side of the suction guide device along a smooth curve, but most of the fluid flows through the impeller 143 along a flow path whose cross-sectional area gradually decreases in the rotation direction of the impeller 143. It flows toward the blade inlet edge 144a of the blade 143, and a portion flows into the blade from the longitudinal edge 144b side of the blade 144.

The configuration according to the present invention in which the suction guide aperture of the suction guide device 146 is expanded to near the outside diameter of the blades of the impeller is proven by the following experiment. The tests were conducted using four types of water pumps with relatively short impeller blades, each with the same blades and the same discharge casing, but with various inlet shapes.

FIG. 3 shows a conventional water pump N001 constructed according to the concept of normal pump design, in which a front ring 33 having an inner diameter corresponding to the diameter of the impeller inlet of an impeller 32 fixed to a rotating shaft 31 is attached. , no suction guide device is provided. 34a is a pump suction port, and 35 is a discharge casing.

FIG. 4 shows a water pump N09 in which the front ring 33 of FIG. 3 is absent, the suction port diameter 34b corresponds to the outer diameter of the same impeller 32, and the suction guide device is not provided.
It is 2.

FIG. 5 shows a water pump N003 equipped with a suction guide device 36 in which the cross-sectional area of a plurality of flow paths gradually decreases in the radial direction toward the blade inlet edge 32a of the impeller 32. The aperture d corresponds to the blade inlet diameter of the impeller 32.

FIG. 6 shows the suction guide diameter d of the suction guide device 36 in FIG.
Water pump No. 4 is equipped with a suction guide device according to the present invention, which is larger than the impeller inlet diameter d and smaller than the impeller blade outer diameter d2.

FIG. 7 graphically shows the experimental results of these four types of water pumps. Here, the rotation speed of the impeller is 7800r,
p, m. Looking at the head characteristic curve, No. 2 has a suction diameter up to the outer diameter of the impeller excluding the front ring.
The head of only N o -1- is reduced, but the other N o -1-,
It can be seen that almost the same head is obtained for No. 4. Furthermore, looking at the shaft power curve, the required shaft power of walk pumps No. 3, No. 4, which are equipped with a suction guide device, is lower than that of water pump No. 1, which does not have a suction guide device, in the high flow range of use. It can be seen that the efficiency is good. Furthermore, it can be seen that the required shaft power does not change even if the suction guide diameter of the suction guide device is changed from the impeller blade inlet diameter to close to the blade outer diameter. As can be seen from these results, the water pump No. 4 of the present invention can transport with less power than the conventional water pump No. 1 and with the same head characteristics as the conventional water pump.

In addition, as a result of experimenting to investigate the effects of the impeller blade length and the gap between the casing and the blades, it was found that with an impeller with a blade length less than or equal to 1, there is almost no effect on the head characteristic curve when the rotation speed is greater than or equal to 1. That's what I found out.

〔Effect of the invention〕

In the present invention, the suction guide aperture of the suction guide device is made larger than the inlet diameter of the impeller, and the suction guide aperture is set to an arbitrary value from the impeller blade inlet diameter to the blade outer diameter. As evidenced by the experimental results, the pump head characteristics remain the same as before, and less power is required, making it easier to design a high-speed pump with a relatively large flow range and making it more versatile.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view of an embodiment of a high-speed turbo pump according to the present invention, FIG. 2 is an end view of the suction guide device of the turbo pump of FIG. 1 taken along line n-tt, and FIGS. FIG. 6 is a schematic diagram of four types of water pumps for cooling internal combustion engines used for comparative experiments of the turbo pump of the present invention;
Fig. 7 is a graph showing the experimental results, Fig. 8 is a vertical cross-sectional view of a conventional small-capacity, high-head turbo pump using a suction guide device, and Fig. 9 is an end view of the suction guide device shown in Fig. 8. be. 143.243--Impeller, 144a, 244a...
・Blade inlet edge, 144,244...Blade, 146,2
46... Suction guide device, 149.249... Suction guide vane, d... Suction guide diameter, d,... Impeller blade inlet diameter, d2... Impeller blade outer diameter

Claims (1)

[Claims] (1) A suction guide device having suction guide vanes that partition a plurality of suction channels finely divided in the circumferential direction is provided on the upstream side of the impeller, and the cross-sectional area of the suction channel is located at the blade inlet edge of the impeller. The suction guide diameter (d) of the suction guide device, which is formed to gradually decrease in the rotational direction of the impeller, is made larger than the blade inlet diameter of the impeller. A high-speed turbo pump characterized by having an arbitrary value up to the outer diameter.