Selection of Optimal Gas-Dynamic Parameters of Radial-Axial Turbines in Their Joint Operation with Reciprocating Internal Combustion Engines

The study of radial-axial (centripetal) turbines is important for science and technology. They are widely used in the refrigeration industry, internal combustion engines, and power engineering, both in the form of auxiliary units and in autonomous power units. The article offers a method for selecting the gas-dynamic parameters of the centripetal turbine in order to obtain the highest efficiency and the best size of the turbine. The increased manufacturability of the turbine is provided due to the absence of a straightener at the outlet of the impeller and the use of straight blades in the impeller. The dependence of the efficiency of a centripetal turbine on the profiles of the blades and the radial dimensions of the nozzle apparatus and the impeller, as well as on the length of the impeller blades is investigated. Considering the recommended optimal parameters, the calculation of a pulsed centripetal turbine operating in conjunction with a four-stroke piston internal combustion engine is performed.

A Computational Study of Gas-Dynamic Parameters of Radial-Axial Turbines and Their Joint Operation with Piston Engines

Radial-axial (centripetal) turbines are widely used in various fields of industry, energy and transport, but their characteristics require improvement, above all increasing the efficiency factor. A differential iterative calculation method is used to calculate the gas dynamic parameters and characteristics of centripetal turbines. The joint operation of a pulsed centripetal turbine and a four-stroke piston engine is examined. The efficiency of the centripetal turbine is strongly dependent on the combination of the turbine’s and piston engine’s geometric features. The study examines the influence of the rotor blades curvature, the ratio of the height of the impeller blades at the outlet to the height of the blades at the entrance, and the number of blades of the impeller and the nozzle device on the turbine efficiency. An approach to the selection of the optimal geometric parameters that provide the highest efficiency of the designed centripetal turbine when it is used jointly with a four-stroke piston engine is proposed.

METHODOLOGY FOR DETERMINING SPEED COEFFICIENTS IN THE DESIGN OF RADIAL-AXIAL TURBINE

The article proposes a method for the interrelated determination of the speed coefficients and optimal geometry of a radial-axial centripetal turbine flow range. The method is based on a model of gas flow at an average diameter in a one-dimensional quasi-stationary approximation, supplemented with ratios to determine the optimal operating parameters of the turbine.

Features of the calculation of the centripetal turbine in the software Numeca

In the article written, processes occurring in a centripetal turbine are considered. The geometry was analyzed, the main elements were selected, the grid was built. In the course of the calculation work, a mathematical model was developed to solve the problem posed, the incoming parameters and the geometry feature were taken into account. The calculations were carried out using the Numeca software. In the course of the work, it was established the effect of temperature changes on some processes occurring in the provided turbine.