Stratospheric Airship Blower Design And Its Characteristics Research

In order to achieve its long-term stay and reusability,stratospheric airships require a reliable and effective environmental control system to achieve their shape and pressure difference during ascent and stay process.The system can be referred to as the "breathing system" of an airship.Blower is a key part of the environmental control system,which enables the air to be blown into the overpressure bladder.Stratospheric airships use blowers that are resistant to pressure differences of several hundred Pascal.In addition,at a height of 20 km,the atmospheric density is very low,which is significantly different from that of a conventional blower.Therefore,the blower used in the stratospheric airship needs to be studied and designed.In this paper,the blower used in the stratospheric airship is taken as the research object,the design of the blower is carried out,and the performance of the air blower is analyzed.A preliminary design and analysis method of centrifugal and axial blowers based on semi-empirical formula was established.The designed blower was simulated by Cfturbo and Pumplinx software to analyze its performance at low and high altitude,which laid the foundation for further research on the blower of airships.The main work of the dissertation is as follows:Firstly,the demand of the blower for the landing of the airship is analyzed.Based on the standard atmospheric environment model,the relationship between the total volume flow of the blower and the descending speed and height in the descending process of a typical airship is analyzed.The total energy required by the blower for the descent of theairship is given,and the types of blowers available for the stratospheric airship and their characteristics are given.Secondly,the one-dimensional characteristic analysis method of centrifugal blower is established.By the relationship between the geometric parameters of centrifugal blower and the energy loss of each component of the blower,a one-dimensional analysis method of blower characteristics is formed.By means of detailed geometric parameters and experimental data of the pump,the effectiveness and the accuracy of the method are verified.The formed estimation method can quickly and accurately give the centrifugal blower characteristics under certain geometric parameters and working conditions,which can be used as a preliminary design tool of centrifugal blower.For the axial blowers,an axial blower is designed to meet the descending needs of a certain stratospheric airship at high altitudes,based on the solitary leaf design method.The three-dimensional model of the axial blower is derived using Cfturbo software.Next,two softwares-the CFTurbo,a high-precision modeling tool that can be used for blower design,and the PumpLinx,a CFD numerical solution-are given.These two softwares allow seamless connection of the blower model to the numerical solution,enabling rapid generation of flow field grids,flow field calculations,post processing and verifying compliance with required steps.The modeling and numerical analysis methods were verified by a standard pump.Finally,centrifugal blower and axial blower were designed according to the specific working conditions under the altitude of 20,000 meters.The characteristics of the air-conditioners and the descending process were analyzed in detail.The conclusion is drawn that the blower efficiency(regardless of the motor efficiency change)and the actual volume flow rate decrease with the decrease of height under the condition of certain input power and pressure difference;as the height decreases,the blower The flow coefficient gradually increases,the pressurecoefficient is gradually reduced,the power factor and efficiency will be gradually reduced.However,its corresponding blower is gradually increasing the specific speed.In addition,the sensitivity analysis of the geometric parameters of the two types of blowers is also made.The key parameters influencing blower characteristics and their influence laws are obtained through the sensitivity analysis of the blower geometric parameters,which can provide references for the optimization design of centrifugal blowers.In addition,according to the design and analysis of the above two kinds of blowers,comparing the advantages and disadvantages of the two kinds of blowers provides the basis for selecting the blower for the different needs of the airships in the stratosphere.