Study On The Effect Of Microgravity Thermal Environment On Human Thermal Comfort

Microgravity thermal environment is an unavoidable environmental factor for human beings' activity in outer space,which affects the astronaut's thermal comfort,work efficiency,even the health.Microgravity will affect the human physiology and thermal environment to some extent.Specifically,the thermoregulation ability can be inhibited by the disappearance of natural convection,redistribution of blood,dehydration,decline of cardiovascular function and restrain of metabolism caused by microgravity directly or indirectly,leading to the damage of thermoregulation,which will affect the human thermal comfort further.Therefore,based on the indexes related to human thermal comfort,such as body weight,thermal regulation system,blood rheology and blood protein,rats were experimented to study the effects of microgravity on the above physiological indexes,which lays foundation for the further research of the impact of thermal environment under microgravity on human thermal comfort and evaluating the thermal environment objectively.Finally,some suggestions are proposed to create the comfortable thermal environment under microgravity.Firstly,this paper expounds the contents of comparative medicine,which provides theoretical support for animal experiment,and illustrates the correlation between human thermal comfort and weight,thermal regulation system,blood rheology,blood protein respectively,which provides a theoretical basis for studying the effects of microgravity on human thermal comfort.Secondly,this paper analyses the heat and moisture transfer characteristics under the microgravity multi-field coupled environment and the effects of microgravity on each item of human thermal balance equation.Then,widely used experimental device was partially improved based on actual condition and the experiment was carried out to study the impact of microgravity,temperature,time on the indexes of weight,the temperature of chest,core temperature,hemorheology,blood protein of rats,the research results are shown as follows:(1)In microgravity and normal state,the rat grows fastest at 18?~ 20?and 18?,respectively;the time and environmental temperature have a significant effect on body weight in normal and microgravity state,respectively;microgravity has a significant effect on body weight from DAY1 to DAY6,especially at 20?and 23?;there is no further interaction between microgravity and environmental temperature;the multiple linear model between weight and time,temperature and gravity is: Y=2.884X1+ 2.720X2+ 18.786X3+ 170.757.(2)The time has a significant effect on chest temperature only in microgravity state;environmental temperature has a significant effect on chest temperature both in microgravity and normal state;microgravity has a significant effect on chest temperature from DAY2 to DAY6,especially at 23?and 26?;there is no further interaction between microgravity and environmental temperature;the multiple linear model between chest temperature and time,temperature,gravity is: Y= 0.076X1+ 0.463X2-0.596X3+ 25.246.(3)The time has a significant effect on core temperature only in microgravity state;environmental temperature has a significant effect on core temperature both in microgravity and normal state;microgravity has a significant effect on core temperature from DAY2 to DAY6,especially at 20?and 26?;there is no further interaction between microgravity and environmental temperature;the multiple linear model between core temperature and time,temperature,gravity is: Y=0.026X1+ 0.097X2-0.328X3+35.292.(4)The environmental temperature has the most significant effect on plasma viscosity,erythrocyte aggregation index,erythrocyte deformability index and hematocrit;the blood rheology performs better at 23?~ 26? from the point of view of whole blood viscosity;the effect of microgravity on blood rheology is the strongest and the weakest at 23?and 20?,respectively;the microgravity has the most significant effect on whole blood reduction viscosity of blood rheology;there is no further interaction between microgravity and environmental temperature.(5)The variation tendency of blood protein index caused by environmental temperature of the microgravity and normal state are the same;body tissue metabolism and other physiological activities performs better at 23? in normal state;the sensitivity ranking order affected by environmental temperature is albumin,total protein,plasma protein and globulin;the effect of microgravity on the blood protein index is the most significant at 23?;the sensitivity ranking order affected by microgravity is ALB/GLB,albumin,globulin,hemoglobin and total protein;there is no further interaction between microgravity and environmental temperature.And then,by conducting experiments again to study the effects on the body thermoregulation system,the results are shown as follows: the effect of microgravity on temperature of hind paw and anus are the most obvious as time goes on while the rest are less obvious;the temperature between hind paw and head,chest and forefoot is significantly different,respectively;the temperature of head,forefoot,chest and core temperature increased by 1.1?,1.1?,0.9? and 0.5?,meanwhile the temperature of hind paw decreased by 1.1?;the vertical temperature gradient between chest and hind paw increased by 3?.Finally,the research results of this study provide an important reference for the design and operation of the cabin air conditioning system;in order to enhance thermal comfort,medicine measures,special measures,component layer design of cabin air conditioning,airflow organization,cabin air disturbance and high temperature emergency design should be taken into account to compete against the appropriate temperature load in cabin.