The System Optimization And Test Analysis Of Thermal Manikin

Thermal manikin is an equipment simulating human's heat transfer.It was used to test clothing thermal resistance and promoted the evaluation of the clothing thermal parameters,the study of the clothing thermal performance,and the development of new garment material.This paper explored thermal manikin's heating scheme and established a feasible solution.It integrated hardware equipment into a case for ease of inspection and management,and wrote a new variable temperature control program based on LabVIEW for clothing thermal resistance test.Finally,the clothing thermal resistance test results of thermal manikin were analyzed and studied.The heating system of thermal manikin could basically be divided into three forms,namely the outer surface,the inner surface and the internal space heating.At the beginning of the research,four different heat source schemes were designed and a simple half-body manikin was used to investigate these four heating methods and analyze their feasibility.The heating cylinder experiment shows that the biggest problem of internal heating is the control of the uniformity of manikin's surface temperature.The experiment of the soft heating film proves that heating the external surface can help the manikin to reach the set temperature quickly,and has better temperature uniformity.Therefore,the research chose to heat the heating wire which is evenly around the outer surface of the thermal manikin.In addition,the heating model of the heating wire,region segmentation and simulated skin materials of thermal manikin are introduced.The hardware system of the manikin developed by this project consists of temperature acquisition system,output voltage control system and other auxiliary equipment.This paper describes in detail the performance of the main hardware devices and shows the connection scheme and work flow of hardware system.In addition,the hardware control system of thermal manikin is very large and it is easy to be damaged if it directly scattered on the ground.Therefore,this paper designed and manufactured a case to arrange hardware in an orderly way for later management.There are two kinds of traditional control methods of thermal manikin,one is to maintain a constant surface temperature,and the other is to maintain a constant heating power,ie,namely constant temperature control method and constant heat control method.Constant-power thermal manikin do not require temperature control,and this can result in skin temperature deviating from reality in different conditions.In previous tests,there was a large deviation in the thermal resistance test measured by constant temperature control method.Therefore,this paper wrote a new LabVIEW program—a variable temperature control system based on the thermal comfort equation to test the clothing thermal resistance,and compared it with the test result of the constant temperature control system.Although the clothing thermal resistance measured by the two test systems are relatively large,the test result of the variable temperature control system is closer to the true value.This paper then carried out a series of theoretical analysis of the cause of the deviation of clothing thermal resistance test results,and conducted a qualitative experimental exploration with a simple manikin.The two groups of qualitative experiments conducted on the simple manikin and the extruded plate confirm the importance of radiation heat transfer to the thermal resistance test.Therefore,this project applied black insulating tape on the surface of thermal manikin to further verify the effect of radiation on heat transfer,and conducted thermal resistance test and comparison.A short sleeve thermal resistance test was performed using a constant temperature control system and a variable temperature control system respectively.The result showed that the thermal resistance of the short sleeve decreased by 6.1% and 7.1% respectively after laying black tape on the surface of the manikin.The result of testing with a variable temperature control system on a thermal manikin is already very close to the true value,with an error of less than 5%.