Research On Characteristics Of Turboexpander And Development Of Emergency Power System

With the progress of society and the increasing quality of life,people have put forward higher requirements for their living environment and quality,and their dependence on electricity is also increasing.This has led to the problem of power security.Emergency power supplies are designed to adapt to this Born by need.The emergency power supply is an independent emergency equipment that can continue to provide short-term power supply to the user’s important load when the normal power supply system is interrupted.At present,traditional emergency power systems represented by small diesel generators generally have disadvantages such as environmental pollution,poor mobility,and poor output power quality,which seriously hinder their further development.It is of great practical significance to accelerate the development of environmentally friendly,portable and small emergency power systems.In this regard,this article proposes a new type of emergency power system that uses high-pressure compressed air as the energy source and turbo-expander as the starter—a small-scale emergency power system based on turbo-expander,which aims to provide users with a safe,reliable,and portable Convenient and environmentally friendly emergency power supply.The main research work of the thesis is divided into the following parts:(1)By investigating the current research status of small emergency power systems and expanders at home and abroad,a new type of emergency power system-a turbo-expander-based small emergency power system was proposed,and the working principle,structure and energy conversion mechanism of the system were clarified..(2)Establish mathematical models of the system based on energy conservation equations,continuity equations,isentropic process equations,etc.,including mathematical models such as gas storage tanks,pressure reducing valves,turbo-expanders,etc.,to provide a theoretical basis for system simulation analysis.(3)Use MATLAB/Simulink to simulate the turbo-expander model,and obtain the relationship curve between the pressure of the gas tank and the output power and torque of the turbo-expander;the relationship curve between the intake pressure and the gas consumption and efficiency of the turbo-expander.(4)In order to improve the intake loss of the turbo expander,explore its internal gas flow characteristics,and solve the problem that the design parameter setting such as speed depends on subjective experience.Based on the orthogonal design method,the turbo expander output power and torque are used as performance indicators,the FLUENT software dynamic grid technology is used to analyze the influence of design parameters such as speed on performance indicators,and the SPSS(Statistical Product and Service Solutions)range method is adopted.Calculate the design parameter combination when the performance index is optimal at the same time,that is,the inlet pressure is 0.8MPa,the speed is 2250r/min,the inlet temperature is 285 K,and the turbo expander output power and torque are the largest,respectively 8.94 k W and 45.05N· m,And observe the pressure field,velocity field and temperature field of the turboexpander;analyze the influence of the installation angle of the Laval nozzle and the diameter of the throat pipe on the internal flow characteristics of the turboexpander and complete the output power and other performance indicators,quantitative calculations.The results show that when the installation angle is 45°,the output torque,power and efficiency reach larger values,which are 20.45N· m,7k W,and 43.88%,respectively.When the throat diameter is 28 mm,each performance index achieves the maximum value,which is 15.98N· m,6.6k W,42.49%.(5)In order to verify the accuracy of the simulation and orthogonal design method,build a system experimental platform and conduct experimental research;according to the actual status of the emergency power system,the experimental research under variable working conditions is completed,and the output power of the turbo expander,Speed,torque and generator output current and voltage are measured and calculated.The results show that the turboexpander and generator have good output stability and can meet the requirements of different power loads of 0～5k W,which provides a practical basis for the turboexpander as the starter of a small emergency power system.