Low Speed Impeller Pump for Hydraulic Energy Conversion Systems 

Description:
The working elements of the water kinetic energy conversion systems develop very small speeds of rotation (1 – 5min^-1). In the case of utilization of these systems for water pumping by high speed pumps (700 – 1500min^-1) it is necessary to have a multiplication system with high multiplying ratio (i=140…1500). This fact leads to the increase of general costs and to the reduction of reliability.  A more advantageous solution consists in the utilization of low speed impeller pumps. This solution is the basis of elaboration of the micro hydropower station for water kinetic energy conversion into mechanical energy for water pumping. Aiming at the above, jointly with SA HIDROTEHNICA, Chişinău, we have elaborated the concept of low speed pump (n=300...500 min^-1), have performed ample computer simulation of water wheels (fig. 1,a), and have designed the construction (fig. 1,b) of two typo-dimensions of impeller pumps (n=300 min^-1; n=500min^-1). Two industrial prototypes of the designed impeller pumps have been executed at HIDROTEHNICA enterprise (fig. 2,a,b) and laboratory experimental testing on the mentioned enterprise’s stand has been carried out. As result of the carried out testing the following has been achieved: mechanical efficiency – 0,7; output factor - 30m³ (number of revolutions n=300 min^-1 ) and 40m³ (n=500min^-1), respectively. Low speed impeller pump are utilized in the microhydrostation structure.

Innovative Aspect and Main Advantages:
The low speed impeller pumps were fabricated at the SA Hidrotehnica enterprise for the first time. Their utilisation in systems, in which the working element performs low speed revolutions, is reasonable as expenses for the multiplication system are reduced. Mechanical efficiency and output of the tested pumps are high.

Areas of Application:
The impeller pumps which have been designed, fabricated and tested, can be utilized for water pumping in cases when the inlet revolution is relatively small (n=300…500min^-1), such as micro hydropower stations for water kinetic energy conversion into mechanical energy for water pumping; wind systems for water pumping, etc.

Stage of Development:
Two typo-dimensions (30m³ and 40m³) of low speed impeller pumps (number of revolutions n=300 min^-1 and n=500min^-1, respectively), have been tested in laboratory conditions. It follows to be tested in real conditions on the pilot micro hydropower station for water kinetic energy conversion into mechanical energy (for water pumping), which will be mounted on the Prut River near Stoienesti village. The low speed impeller pumps with updated specifications can be produced at the Hidrotehnica enterprise, Chişinău.

Fig.1 Computerised 3D model and design of the low speed impeller pump


Fig.2 Industrial prototypes of the impeller pumps: a) n=300 min^-1, Q=30m³; b) n=500min^-1, Q=40m³


Fig.3 Technical characteristics of impeller pump, n=500min^-1, Q=40m³

Contact Details:
Technical University of Moldova
Contact persons:
Ion Bostan, Valeriu Dulgheru
Address:
Republic of Moldova, Chisinau, 168, Stefan cel Mare Ave., Centre for the Elaboration of Renewable Energy Conversion Systems (CERECS)
Tel/Fax:
+ (373 22) 23 78 61,
+ (373 22) 44 50 88
E-mail:
bostan@adm.utm.md;
dulgheru@mail.utm.md