Experimental studies workshop pump in different modes

Abstract

In recent years, the type of new management - the cultivation of high-algae algae as raw materials for pharmacology and perfumery, as well as for food and feed purposes - is developing. At the same time, the absence of adequate means of mechanization of these technologies in Ukraine constrains this process, in particular, in the cultivation of algal spirulina, there are no effective means for pumping a suspension of culture.

The purpose of the work is to substantiate and adjust the ratio between the pressure on the liquid, the productivity, power and the speed of the rotor of the impeller.

Materials and methods of research. The analysis of the axial pump operation was carried out using the provisions of the theory of hydraulics of liquids and statistical methods for processing the results of research on an experimental installation in the MathCAD, Excel system.

Research results. Experimentally determined numerical values of the efficiency coefficients for the developed axial pump at different rotational speeds of the impeller. All efficiency except hydraulic, with increase of rotation frequency of a pump impeller increase. The increase in mechanical efficiency is explained by the fact that the increase in the speed of rotation increases the supply height. This leads to an increase in drive power. Mechanical losses of power practically remain unchanged, that is, their share in the general background of the use of power falls, which is reflected in the mechanical efficiency. Increasing the volume efficiency at an increase in the speed of rotation is associated with a decrease in leakage through the gap between the impeller and the pump housing. Reducing hydraulic losses when reducing the speed of rotation is associated with a decrease in the speed of fluid flow through the pump, that is, reducing vortices, losses on impact at the entrance and exit.

Conclusions and perspectives. When operating a pump in a closed network and reducing the rotational speed of the impeller by more than 10% of the rated power, supply, and pressure for this pump at the current rotational speed, the ratio of these parameters to the fractional components of the efficiency of the pump must be entered. The calculation error does not exceed 5%.

Keywords. Microalgae, suspension, illuminating surface, axial pump, liquid pressure, performance, power, speed of rotation.

Topicality. In recent years, the type of new management - the cultivation of high-algae algae as raw materials for pharmacology and perfumery, as well as for food and feed purposes - is developing. At the same time, the absence of adequate means of mechanization of these technologies in Ukraine constrains this process, in particular, in the cultivation of algal spirulina, there are no effective means for pumping a suspension of culture.

Analysis of recent research and publications. The industrial cultivation of microalgae is carried out in special cultivating plants, which have a wide branching of water lighted surfaces of the plant is of great importance. As a rule, water pools are equally spaced. This makes it possible to mix the suspension using blade mixers, but on the other hand - the area used to accommodate the plant is not effectively used. The ability to place trays in height is not used, which is very important for energy saving in temperate climates. To mix the suspension in such plants, we need devices that do not destroy the algae cells and create a small pressure to feed the sun-drop to a height of 5...10 m, like axial pumps.

The purpose of the research: to substantiate and match the relationship between the pressure of the liquid, the productivity, power and frequency of the rotation of the impeller impeller.

Materials and methods of research. The analysis of the axial pump operation was carried out using the provisions of the theory of hydraulics of liquids and statistical methods for processing the results of research on an experimental installation in the MathCAD, Excel system.

Research results. For blade machines, the ratio between pressure, productivity, power and rotational speed of the impeller is known. But these ratios are valid for some of the coefficients of efficiency (efficiency) of a pump, that is, when it is running on an open network. As a rule, when changing the rotational speed of the pump, the efficiency of the pump varies from 0 to 50%. To use these ratios it is necessary to conduct a more detailed analysis of the efficiency of the pump.

The pump power is determined taking into account the total efficiency. The total efficiency is determined from the product of three fractional coefficients: hydraulic, volume and mechanical.

In the work, the numerical values of the efficiency coefficients for the developed pump are determined experimentally at different rotational speeds of the impeller.

All efficiency except hydraulic, with increase of rotation frequency of a pump impeller increase. The increase in mechanical efficiency is explained by the fact that the increase in the speed of rotation increases the supply height. This leads to an increase in drive power. Mechanical losses of power practically remain unchanged, that is, their share in the general background of the use of power falls, which is reflected in the mechanical efficiency. Increasing the volume efficiency at an increase in the speed of rotation is associated with a decrease in leakage through the gap between the impeller and the pump housing. Reducing hydraulic losses when reducing the speed of rotation is associated with a decrease in the speed of fluid flow through the pump, that is, reducing vortices, losses on impact at the entrance and exit.

Conclusions and perspectives

When operating a pump in a closed network and reducing the rotational speed of the impeller by more than 10% of the rated power, supply, and pressure for this pump at the current rotational speed, the ratio of these parameters to the fractional components of the efficiency of the pump must be entered. The calculation error does not exceed 5%.