The current state and development of pump technology in our country.

1.The sources of pump product drawings in China can be divided into joint design, introduction, independent development, and other categories.

(1) For jointly designed products, research institutions led by the Shenyang Pump Research Institute organized relevant pump factories to conduct joint design of various types of pumps from the 1960s to the 1980s. Examples include IS (IB) type single-stage single-suction centrifugal pumps; IH type chemical pumps; S (SH) type double-suction centrifugal pumps; D (DG) type segmented multi-stage pumps; W type vortex pumps; Y type oil pumps; JC type deep well pumps; HW type mixed-flow pumps; QJ type deep well submersible pumps; IR type hot water pumps; BPZ type sprinkler self-priming pumps; FY type corrosion-resistant submerged centrifugal pumps; and 3G type three-screw pumps.These products were all leading domestic products at that time and are still in production today. However, the structure (shape) and performance indicators of some products are relatively outdated and should be gradually replaced by new-type products.

(2) For imported products, China introduced very little pump technology before the 1980s. In the early stage of reform and opening up, a large amount of pump technology was introduced from foreign countries. With the continuous entry of foreign pump companies into China in the form of joint ventures or wholly foreign-owned enterprises, some new pump product technologies were also brought in. Examples include: slurry pumps from Shibeng-Wolman; submersible electric well pumps from Shibeng (Tianjin Electric Machinery Factory) - Germany Ritz Company; boiler feed pumps from Shenyang Pump (Shanghai Pump) - Germany KSB Company; boiler feed pumps from Shanghai Electric Power Maintenance and Manufacturing Factory - UK Weir Company; condensate pumps from Shanghai Pump Factory - KSB Company; condensate pumps from Changsha Pump Factory - Japan Hitachi Company; CZ, ZA (ZE) and other chemical process pumps from Dalian Acid-Resistant Pump Factory - Switzerland Sulzer Company; sewage pumps from Shanghai Pump Factory - US Dresser Company; water ring vacuum pumps from Foshan Pump Factory - Germany Siemens Company; hot water pumps and marine pumps from Shanghai Pump Factory - KSB Company; screw pumps from Tianjin Industrial Pump General Factory - Germany Allweiler Company; marine pumps from Tianjin Industrial Pump General Factory - Japan Daiko Company; submersible sewage pumps from Nanjing Deep Well Pump Factory - Germany ABS Company; large vertical diagonal flow pumps from Changsha Pump Factory - US Ingersoll Company; high-lift multi-stage centrifugal pumps from Shanghai No.1 Pump Factory - UK M·J Company; and phosphoric acid pumps from Xiangfan 525 Factory - France H·S Company.These imported pump products feature mature technology and advanced performance, which have played an important role in promoting the development of China's pump technology and have become the mainstay of China's pump products, still being mass-produced today. Some of these products, however, have issues in terms of structure or performance and require further improvement.

(3) Products from foreign-invested (wholly foreign-owned) pump enterprises in China include: Shanghai KSB-Omega (RDL) double-suction pumps, boiler feed pumps, and condensate pumps; 嘉立特 (茬原) - chemical process pumps; Foshan (Andritz) - pulp pumps; Nanjing Goulds - ISO type single-stage single-suction centrifugal pumps and P type segmented multi-stage centrifugal pumps; Dalian Teikoku - canned motor pumps; Shenyang Flygt - submersible sewage pumps; Suzhou Grundfos - stamped pumps; and Lanzhou Netzsch - screw pumps. Most of these products are of better quality than domestic products. Despite their higher prices, they sell well.

(4) Independently developed products include AY oil pumps; TSWA multi-stage centrifugal pumps; ZJ slurry pumps; pipeline pumps; direct-connected pipeline pumps; high-rise water supply pumps; air-conditioning pumps; submersible sewage pumps; vertical sewage pumps; submersible axial-flow pumps (mixed-flow pumps); double-suction pumps, and pulp pumps. Most of these products have low levels of generalization and standardization, and their performance needs to be further improved

2.From partial import to basically full localization of key pump products:

Due to the introduction of products and the entry of well-known enterprises such as KSB, China's pump production capacity has been significantly improved. Basically, all major key pumps required by national economic sectors can now be produced domestically. Examples include: supercritical boiler feed pumps (with a temperature and pressure of 25-35MPa); high-speed pumps and high-pressure multi-stage pumps for ethylene and hydrogenation units; high-pressure descaling pumps for steel plants; large-scale water transfer pumps for the Dongshen Water Supply Project and the South-to-North Water Diversion Project; large-flow and high-lift (1000m) drainage pumps for mines; flue gas desulfurization pumps for power plants; and high-temperature oil slurry pumps for refineries.

3.Wide application of new technologies led by CAD:

(1) CNC machine tools have begun to be used in the processing of pump molds, impellers, and important components, which can improve the manufacturing quality of pumps. Figure 1 shows the axial-flow pump impeller processed by a CNC milling machine and the 3D drawing of the impeller used for processing.(Axial-flow pump impeller processed by a CNC milling machine and the 3D drawing of the impeller used for processing)

(2) Hydraulic design and profiling software for pumps have gradually replaced manual calculation and drawing. Some people ask about the efficiency of pumps designed with this software, which is a question from laymen. No matter how good the software is, it needs to be used by people, and the designer's design concepts and experience can be integrated into it. Moreover, it is fast and accurate. Figure 2 shows the hydraulic drawing of a spiral centrifugal pump impeller designed with JP1 software, which only takes 10 minutes to design, while manual design may take two days(Hydraulic drawing of a spiral centrifugal pump impeller designed with JP1 software)

(3) The calculation of the internal flow field of pumps has advanced from quasi-3D inviscid flow to full 3D viscous flow. The main method for quasi-3D inviscid flow calculation is the iteration of two types of flow surfaces, S1 and S2. It reduces the 3D flow to 2D flow, that is, solving the 3D flow problem by iteratively solving the flow on the meridian plane (axial plane) and any rotating surface (flow surface). Since the complex 3D flow is simplified to 2D for solution, the accuracy of the solution is affected. In recent years, Computational Fluid Dynamics (CFD for short) has been developed, providing new ideas and methods for the flow field calculation of fluid machinery. To calculate the flow field using CFD, first, the calculation area is modeled as a 3D solid, then the mesh is generated, and finally, commercial CFD software such as Fluent is used for calculation, as shown in Figure 3.(CFD)

(4) For the measurement of the internal flow field, probes were often used in the past. On the one hand, the probe itself has a great impact on the flow; on the other hand, the conversion device for measuring the rotating flow field is also very complex. Further, the Laser Doppler Velocimeter (LDV) is used, which irradiates particles in the flow with laser, and the light is scattered by the particles. The flow velocity is measured based on the degree of scattering. This method has become mature and widely used, but it generally only measures a certain component of the velocity at a single point. Now, Particle Image Velocimetry (PIV) has begun to be used. Its working principle is to disperse tracer particles in the flow field, irradiate the flow field with a pulsed sheet light source, and record the particle images on a negative film through two or more consecutive exposures, thereby obtaining the velocity distribution of the flow field. This method breaks through the limitation of traditional single-point measurement, enabling instantaneous non-contact measurement of the velocity distribution on a cross-section, and has high measurement accuracy.

(5) Optimization design methods: To improve the performance of pumps, many scholars have conducted research on optimization design methods. Summarily, there are mainly the following methods: the velocity coefficient optimization method based on statistical data of excellent models; the loss extremum optimization method aiming at minimizing hydraulic loss; and the criterion screening optimization method with a certain index as the objective function. It is worth noting that the current optimization design methods may only have guiding significance for the design of specific pumps. In addition, the advent of advanced technologies such as CFD has largely reduced the interest in optimization design, and the number of scholars researching optimization design methods has gradually decreased in the past two years.

4.Progress in non-clogging pump and low-speed pump technologies:

(1) The non-clogging pump design methods summarized independently in China have basically reached a practical level. The design methods widely used in China mainly include: designing double-channel impellers based on the cross-sectional variation law along the flow channel centerline; designing spiral centrifugal impellers using the square grid conformal transformation method; and designing swirling impellers based on three factors: the outer diameter of the impeller, the maximum outer diameter of the volute, and the throat area.

(2) The research on the theory and design of low-specific-speed pumps has been extensive and in-depth. The overload-free design method has been promoted and applied, and good results have been achieved by using long and short blades and offset short blades.

5.Axial-flow pump models have reached the advanced level of similar foreign models:

From September 25, 2004, to January 16, 2005, 27 models nationwide participated in the Tianjin joint test of pump models for the South-to-North Water Diversion Project organized by the Ministry of Water Resources. This test was well-led, well-organized, supervised impartially, and had accurate data. The specific speed of the models ranges from 500 to 1500, basically covering the application scope of axial-flow pumps. Compared with the original models, the efficiency has increased by about 2% and the flow rate by about 5%. The average efficiency of 7 models at different angles exceeds 85%, which has reached the advanced level of similar foreign models. Most of the low-lift pumps for important national projects such as the South-to-North Water Diversion Project will be selected from these models.