Abstract

To absorb the power generated by a free turbine, hydraulic brake systems of various designs are used in ground tests of aircraft turboshaft gas turbine engines. Ground tests of aircraft turboshaft gas turbine engines with the use of such hydraulic brakes can result in emergency modes of automated engine control in the area of operation of a free turbine speed regulator. Mismatch between the hydraulic brake loading characteristics and the loading characteristics of the rotor driven by a free turbine of the engine is the main cause of emergency operation of automated control systems.The presented experimental loading characteristics of the hydraulic brake and the helicopter rotor show their significant difference in terms of gain. To eliminate this difference, a possibility of modeling dynamic parameters of rotors by simple automation means was considered. To solve this problem, a linear dynamic model and a block diagram of an automated hydraulic brake control system for ground testing of turboshaft gas turbine engines were elaborated. The law of regulation of the hydraulic brake loading was substantiated. A structurally dynamic diagram of the developed automated control system was presented and calculation formulas for determining the regulator parameters were given. Transient characteristics of the hydraulic brake unit without automation means and with the use of an automated loading control system were calculated. The presented calculation results have shown that the use of automation make it possible to fully emulate characteristics of the helicopter rotors

Highlights

  • Unsatisfactory operation of systems for automatic regulation of free turbine rotation speed is often observed in ground tests of turboshaft gas turbine engines

  • Ground tests of helicopter turboshaft gas turbine engines (GTE) with a free turbine are most often performed on hydraulic brake units to absorb power generated by the FT

  • The study objective: development of an automated control system (ACS) for a hydraulic brake unit designed for ground testing of turboshaft gas turbine engines

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Summary

Introduction

Unsatisfactory operation of systems for automatic regulation of free turbine rotation speed is often observed in ground tests of turboshaft gas turbine engines. Ground tests of helicopter turboshaft gas turbine engines (GTE) with a free turbine are most often performed on hydraulic brake units to absorb (utilize) power generated by the FT. In this case, a free turbine with a connected hydraulic brake (FT+HB) is the object of control. This difference can lead to unsatisfactory operation of the free turbine speed regulator (FTSR) during ground tests of the engine in conjunction with HB. It is relevant to search for solutions that will provide emulation of specified characteristics with simple automation tools

Literature review and problem statement
The aim and objectives of the study
Mathematical description of the study object
Substantiation of the law of regulation by HB loading
Results obtained in the computational studies
Conclusions
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