Time filter

Source Type

Li F.,Nanjing University of Aeronautics and Astronautics | Wang P.,Aerospace Life Support Industries Ltd | Li Y.,Hong Kong Polytechnic University
Applied Mechanics and Materials | Year: 2011

A model of heat and moisture transfer in human-clothing with PCM-environment system is developed. In the model, the improved 25-node model is used for simulating human thermoregulation, and the coupled heat and moisture model is applied to the PCM's clothing. The model predictions and experimental data are compared. Also, the influences of the PCM on human skin temperature and sweat accumulation are predicted. The results are helpful to design of thermal functional clothing. © (2011) Trans Tech Publications. Source

Qiu Y.,Beihang University | Wu W.,Beihang University | Yuan X.,Beihang University | Xiao B.,Aerospace Life Support Industries Ltd | Ren Z.,Institutes of Aviation Medicine
Chinese Journal of Mechanical Engineering (English Edition) | Year: 2012

The body temperature of pilots wearing anti-G garments becomes uncomfortably or even dangerously high in moderate to hot environments. To reduce the body heat stress, thermal characteristics and thermal protection performance of anti-G garments should be studied systematically, but up to now there is no related research to simulate the anti-G garment thermal protection performance. First, a human thermoregulation model is established which can analyze blood convective heat exchange and the central blood temperature fluctuation, according to this model the heat and mass transfer processes of a thermal system are simulated which consists of human body, an anti-G garment, and the surrounding environment, then on the base of this thermal system simulation influences of clothing permeability, thermal resistance and bladder coverage on anti-G garments are analyzed. Calculation of the human thermoregulation model is carried out by using finite element method. Experiments are conducted in 35°C and 40°C climate chambers, and model built above is well validated by these experiments. Model simulation reveals that low thermal resistance and high permeability of anti-G garments reduce body heat stress in moderate environments. In hot environments, however, anti-G garments with lower thermal resistance increase body heat stress. The body heat stress rises significantly as the bladder coverage area of anti-G garments increases. Anti-G garments thermal parameters can be appropriately designed by using the model built in this paper to ensure body physiological requirements. © Mechanical Engineering Society and Springer-Verlag Berlin Heidelberg 2012. Source

Liu F.,Nanjing University of Aeronautics and Astronautics | Tong M.-B.,Nanjing University of Aeronautics and Astronautics | Song J.,Shanghai Aircraft Design and Research Institute | Tan S.,Aerospace Life Support Industries Ltd
Kongqi Donglixue Xuebao/Acta Aerodynamica Sinica | Year: 2010

According to some rules aim to the situation of escape system field, a feasible type of stabilization fins for the domestic ejection system is designed. In this paper, a numerical calculation approach based on CFD is presented to analyze the static and dynamic characteristics of the seat/occupant system with and without fins in a high speed. By comparison, the results of seat/occupant system without fins agree well with the wind tunnel experiment data. The results compared seat/occupant system without fins with seat/occupant system with fins show that the yaw-stability of seat/occupant system with stabilization fins has a perceptible improvement and the fins have no negative effect on the pitch-stability and the roll-stability. The real simulation of the ejection process is implemented by a six degree of freedom dynamic calculation. Numerical calculation can be applied to the ejection seat aerodynamic research. Design of the stabilization fins offers certain reference value to the engineering application. Source

Zhang M.,Northwestern Polytechnical University | Wu M.,Aerospace Life Support Industries Ltd | Wu L.,Aerospace Life Support Industries Ltd
Xibei Gongye Daxue Xuebao/Journal of Northwestern Polytechnical University | Year: 2015

An attitude-control algorithm for "H" structure of ejection seats is presented in this paper. Fuzzy control algorithm is designed based on time-sharing strategy, and simulation is achieved under Matlab/Simulink in accordance with different ejection conditions. The influence of safe altitude caused by algorithm is analyzed, and the minimum safe altitude is compared with K36D-3.5A, ACES II and 120 ejection conditions in GJB 1800A-2007. The simulation results and their analysis show preliminarily that the fuzzy control algorithm for "H" structure of ejection seats can improve escape performance at low speed and adverse attitude, thus proving the algorithm in this paper to be reliable and effective. Source

Qiu Y.,Beihang University | Jiang N.,Aerospace Life Support Industries Ltd | Wu W.,Beihang University | Zhang G.,Beihang University | Xiao B.,Aerospace Life Support Industries Ltd
Chinese Journal of Aeronautics | Year: 2011

To investigate thermal protection effects of heat sinking vest with phase-change material (PCM), human thermoregulation model is introduced, and a thermal mathematical model of heat transfer with phase change has been developed with the enthalpy method. The uniform energy equation is constructed for the whole domain, and the equation is implicitly discreted by control volume and finite difference method. Then the enthalpy in each node is solved by using chasing method to calculate the tridiagonal equations, and the inner surface temperature of PCM could be obtained. According to the human thermoregulation model of heat sinking vest, the dynamic temperature distribution and sweat of the body are solved. Calculation results indicate that the change of core temperature matches the experimental result, and the sweat difference is small. This thermal mathematical model of heat transfer with phase change is credible and appropriate. Through comparing the dynamic temperature distribution and sweat of the body wearing heat sinking vest to results of the body not wearing this clothing, it is evident that wearing heat sinking vest can reduce the body heat load significantly. © 2011 Chinese Journal of Aeronautics. Source

Discover hidden collaborations