Floating Mechanism Research And Algorithm Development Of Latex Weather Balloon Based On Thermal And Dynamic Models

With the deepening of exploration and understanding of near space,high-altitude balloons,as one of the main platforms for near space research,have become increasingly widely used in military,civilian and other fields.In meteorological surveys,due to the high cost of zero-pressure and over-pressure balloons,ordinary latex balloons cannot achieve high-altitude float and are difficult to meet the task of intensive observation at a specific time and place,which limits the improvement of the level of meteorological detection.In response to this dilemma,double latex balloons with low cost that can achieve high-altitude float were developed,but the success rate of their release highly depend on the precise control of the amount of hydrogen.In this paper,the mechanism and algorithm for the float of latex balloon based on thermal and dynamic models are studied.The main research contents and results are as follows:(1)The buoyancy of a single latex balloon is derived and calculated.The influence of the pressure difference between the inside and outside of the balloon and the change of day and night temperature on the buoyancy is analyzed.The relationship between the neutral buoyancy height and the ratio of buoyancy to gravity;By establishing a algorithm model,the vertical trajectory is simulated and predicted.The results show that when the drag coefficient is 0.45,the simulation prediction results are in the best agreement with the test results.(2)The high-altitude floating mechanism of the double latex balloon is explored through test data.The influence of the amount of hydrogen and day-night temperature changes on its movement is derived.Through the establishment of geometric model and dynamic model of the double latex balloon,the vertical trajectory of its lift-off and float process is simulated and predicted,which explores the influence of the amount of hydrogen on the floating altitude.The results show that the amount of hydrogen of the inner balloon is the main factor that determines the floating altitude,and is affected by day-night temperature changes.For every increase or decrease of 0.04kg in the tension of inner balloon,the final floating altitude will correspondingly increase or decrease by about 5 km,while the amount of hydrogen in outer balloon has no effect on its floating altitude.(3)The heat source during the lift-off and floating of the double latex balloon is analyzed.Then a thermal model through thermodynamic differential equations is established.A vertical trajectory prediction algorithm based on the thermal and dynamic models is developed,and the results show that this algorithm can effectively predict the trajectory and movement of the double latex balloon.Comparing the predicted floating altitude with the test data,the accuracy reaches 9 7.7%.(4)Based on the vertical trajectory prediction algorithm,a software that can accurately calculate the optimal amount of hydrogen is developed.The software can also achieve trajectory prediction,data comparison and export functions.Through the field test verification of the accuracy and feasibility,it is proved that the prediction accuracy of the outer balloon explosion time,outer balloon explosion altitude and final floating altitude reaches more than 90%,which can be applied to actual release and improve the success rate of launch.