Preliminary Design of Radial Turbine

ISESCO JOURNAL of Science and Technology, 2015

A design process of radial turbines especially used in turbo charging has been taken in this experiment. Much consideration was given to the techniques with which the designer can estimate the principal dimensions and overall form of a radial turbine in order to meet a given performance requirement. The procedures presented here took into consideration a design process of the radial turbine. Any preliminary design procedure must make assumptions about a number of critical parameters which must be refined as the design progresses through its various stages. Firstly, the designer has to specify the geometry of the turbine together with any assumptions about possible losses from which to calculate an efficiency value. The procedure is then followed in order to produce estimates of performance parameters such as mass flowrate, expansion ratio, power output and efficiency. The procedure's input is the performance specification at the design point which may include power output, mass flow rate, and rotor speed. The output is the basic dimension of the inlet and exit lanes of the rotor in terms of diameter, blade height and angle.

Volume 1: Compressors, Fans and Pumps; Turbines; Heat Transfer; Combustion, Fuels and Emissions, 2017

Turbochargers are used in internal combustion engines to increase their volumetric efficiency and power. Turbochargers consist of a centrifugal compressor driven by a radial turbine. Radial turbines convert the excess kinetic energy in the exhaust gases to power. Vane less radial turbine consists of a volute and a turbine wheel. It is preferred because of its low cost, robustness and good off-design performance. In this study, a radial turbine wheel and volute are designed to meet the power and efficiency requirements. A number of trials are carried out, and the design, which gives the necessary performance and meets the customer requirements, is chosen. The design is analyzed using a validated 3D Navier-Stokes (NS) solver, viz. ANSYS-CFX software at both design and off-design conditions and turbine characteristics are generated.

This is a report for design process of radial turbine used in turbocharger. Input for design requirements are power, mass flow rate, inlet temperature, pressure and rotation speed. The design variables include rotor radius ratios, stator-exit angle and rotor-exit tangential velocity distribution. The geometry was tested using Computational Fluid Dynamics (CFD) where some modifications were introduced on the preliminary design to satisfy the design requirements. The turbine's design point rotational speed is 60000 rpm, stagnation inlet temperature and pressure are 1050K, 3.39 bar respectively and mass flow rate is 0.55kg/s. The turbine rotor has 15 blades with inlet and exit diameters 102mm and 36 mm.

Global Journal of Researches in Engineering, 2013

The combustion chamber of an automobile gas-turbine engine can be designed to produce a gas temperature distribution at the inlet of the turbine increasing from blade root to blade tip. It is shown in the paper, by means of comparative calculations, that by using such distributions of temperatures blade life can be substantially increased, or else, un expensive materials can be used. Such gas temperature distributions produce non-isentropic flow conditions. It is developed in the paper a method for the aerodynamic design of blades within a non-isentropic flow and it is also shown that if the blades are designed by taking an average gas temperature, as it is usually made, important errors are introduced in the resulting shape of the blade, which reduces the efficiency of the turbine.

Volume 2: Aircraft Engine; Marine; Microturbines and Small Turbomachinery, 1988

This paper summarizes the development of variable area radial turbines for small turbochargers, intended for passenger car applications. Comparisons of aerodynamic performance of several different kinds of variable radial inflow turbines are discussed. The results of comparative performance evaluations indicate the scroll area control type (VI) is the most suitable design for small turbochargers, where performance, cost and durability are the major design considerations.

This paper details a physically based methodology to perform an extrapolation of the radial turbine performance maps, both mass flow characteristics and the efficiency curve. This method takes into account a narrow range of experimental data, which is usually the data available when such turbines are part of a turbocharger. Therefore, the extrapolation methodology is especially useful when data from third parties are being used or when the compressor of a turbocharger is used as the turbine brake in a gas stand. The nozzle equation is used to develop an interpolation and extrapolation of the mass flow rate trough the turbine. Then, specific information is extracted from this extrapolation and is fed into a total-to-static efficiency equation to carry out an extension of the efficiency curve. This equation is developed using the definition of the total-to-static efficiency, velocity triangles and thermodynamic and fluid fundamental equations. This procedure has been applied to five radial turbines of different sizes and types. Results are compared against experimental information available in the literature or provided by the turbine manufacturers and a good agreement has been found between theoretical and experimentally estimated data.

Energy Conversion and Management, 2012

This paper details a physical based methodology to perform an extrapolation of the radial turbine performance maps, both mass flow characteristics and the efficiency curve. This method takes into account a narrow range of experimental data, which is usually the data available when such turbines are part of a turbocharger. Therefore, the extrapolation methodology is especially useful when data from third parties are being used or when the compressor of a turbocharger is used as turbine brake in a gas stand. The nozzle equation is used to develop an interpolation and extrapolation of the mass flow rate trough the turbine. Then, specific information is extracted from this extrapolation and is fed into a total-to-static efficiency equation to carry out an extension of the efficiency curve. This equation is developed using the definition of the total-to-static efficiency, velocity triangles and thermodynamic and fluid fundamental equations. This procedure has been applied to five radial turbines of different sizes and types. Results are compared against experimental information available in the literature or provided by the turbine manufacturers and a good agreement has been found between theoretical and experimentally estimated data.

IAEME Publication , 2021

The energy exhaust recovery in engines is obtained using turbochargers which are widely used in the automotive industry. A turbocharged engine leads to a better overall system efficiency and a reduction in exhaust emissions compared, at constant power, with a naturally aspirated engine. The numerical approach in the present work is to explore ways of improving the performances of the radial inflow turbine. This work investigates the performances of a radial inflow turbine under steady states conditions and how they are affected by the rotor geometry. The radial inflow turbine is investigated numerically using 3D Reynolds averaged Navier-Stokes equations, the objective hear is to determine the optimum of performance characteristics of the turbine. The building of the geometry and the generation of unstructured meshes are achieved using ANSYS-ICEM software whereas in order to simulate the flow, the ANSYS-CFX code is applied. The numerical method is also used to determine optimum geometrical characteristics such as the optimum of blade number. It has been found that the rotor with 12 blades gives better performances.

2004

In recent years, looking to the advantages of radial inflow gas turbine much research is focused in this area. The various applications like auxiliary drives in aircraft engine and automobile application where very high speed, compact size and greater specific power are the prime requirements, radial inflow is there by choice. The present work for the design of nozzle-less radial inflow turbine begins with power requirement of 20 kW, the parameters like temperature; pressure and mass flow rate required for the design are obtained from the detailed gas turbine cycle analysis. Based on the available data from cycle analysis initially preliminary design of rotor was developed, from the available loss models the efficiency of the turbine was found. The preliminary design provides the leading dimensions of the rotor with inlet and exit conditions. The objective of most designs will be to maximize the efficiency and/ or to develop the compact size. After completion of the preliminary design of turbine, it was felt necessary to optimized the result for best efficiency accordingly an analytical study was undertaken to study the influence of different parameters like inlet absolute Mach number, relative exit Mach number, solidity, relative velocity ratio and hub to shroud radius ratio on efficiency. VISUAL BASIC program is developed to study the effect of different parameters on efficiency. From the detailed loss analysis the selection of these parameters can be made to achieve optimum performance. It is believed that present work will provide necessary guidelines for the optimal design of radial inflow gas turbine.

Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science, 2018

A new design of a mixed flow variable geometry turbine is developed for the turbocharger used in diesel engines having the cylinder capacity from 1.0 to 1.5 L. An equivalent size radial flow variable geometry turbine is considered as the reference for the purpose of bench-marking. For both the radial and mixed flow turbines, turbocharger components are manufactured and a test rig is developed with them to carry out performance analysis. Steady-state turbine experiments are conducted with various openings of the nozzle vanes, turbine speeds, and expansion ratios. Typical performance parameters like turbine mass flow parameter, combined turbine efficiency, velocity ratio, and specific speed are compared for both mixed flow variable geometry turbine and radial flow variable geometry turbine. The typical value of combined turbine efficiency (defined as the product of isentropic efficiency and the mechanical efficiency) of the mixed flow variable geometry turbine is found to be about 25%...