Numerical Simulation Of The Influence Of Altered Gravity On Human Cardiovascular System

With the rapid development of space and aeronautical science,providing the comfortable and healthy environment as well as improvingthe work efficiency of the astronaut are the cohesiveness objective of thescientists all around the world. It has been proved that the weightlessnessor micro-gravity environment can redistribute the blood flow and affectthe regular function of the human cardiovascular circulatory system, andwhat’s worse, it may cause the astronaut feel uncomfortable and impedethe completion of the task. Therefore, researching for the influence of theweightlessness/micro-gravity environment on the human cardiovascularcirculatory system and searching for the change law of the physiologicalparameters are significant in aerospace field. It can prevent the harmfuleffect on the cardiovascular circulatory system, ensure the environmentbe comfortable and healthy and improve the work efficiency of theastronaut.Currently, the methods for cardiovascular circulatory system studyare divided into test methods and modeling and simulation methods. Thetest methods include human test and animal test and are limited by ethics,technology and the highly cost of time and money. However, themodeling and simulation methods can break out the limitations of testmethods and are effective means for studying cardiovascular circulatorysystem.The simulation model of human cardiovascular circulation system isestablished in Simulink/Matlab platform based on the Windkessel modeltheory. The effect of the gravity on the hydrostatic pressure of the bloodhas been included. The model is used to simulate the parameters ofcardiovascular circulatory system under basal gravitational environmentand is verified by the experimental results. The influences of theweightlessness/micro-gravity environment on the physiologicalparameters have been simulated as well. It is found that the pressurecurves of the systematic artery and the left ventricle have the same shapein all kinds of the gravitational environment. The diastolic blood pressureand the systolic blood pressure decrease and the left ventricle pressure increase with the reduced gravity. The influence of the gravity on thehemodynamic parameters is also presented. The results show that themean arterial pressure and heart rate increase with the increasing of thegravity.Our model is characterized by the high running speed, the highsimulation accuracy and the wide range of application, although it is onlyan initial attempt. It lays the foundation of researching the effect ofgravity change on the blood flow redistribution, establishing the humanthermoregulation model fit for the weightlessness/micro-gravityenvironment and improving the thermal comfort for the astronaut.