Study On The Effect Of Local Diffuse Oxygen Enrichment And The Method Of Creating Oxygen Environment In Sleeping Environment At High Altitudes

The special low-pressure and oxygen-deficient environment in high-altitude areas can easily cause problems such as difficulty in falling asleep and sleep difficulties for foreign people such as Tibet construction and assistance to Tibet,business travel and scientific research,leading to and causing damage to daytime functions such as work and learning efficiency,and seriously threatening human physical and mental health.The creation of a suitable oxygen-rich environment for sleep can be an effective means to improve the quality of human sleep in the plateau.At present,the diffuse oxygen supply in whole space and diffuse oxygen supply in local space has gradually become common methods for indoor oxygen enrichment in plateau buildings.The local diffuse oxygen supply method is to directional and quantitatively supply oxygen-enriched gas to the local space through the oxygen supply port.Compared with the full-space diffuse oxygen supply,the local diffuse oxygen supply method has a shortened orientation for the personnel activity space.Oxygen supply and the oxygen transmission distance are short and improved.Compared with the full-space diffuse oxygen supply,the oxygen enrichment efficiency is higher and the energy consumption is fewer potential advantages.For the sleeping environment,the range of activities of personnel is fixed and the oxygen-enriched target space is bounded.It has the prerequisites for achieving energy-saving and high-efficiency oxygen-enrichment in nearby spaces by using local diffuse oxygen supply.Therefore,the creation of a local oxygen-enriched environment in nearby spaces is an improvement.However,the existing research on high-altitude diffuse oxygen supply mainly focuses on the physical flow characteristics of oxygen,and seldom focuses on the oxygen enrichment effect and enrichment effect of the partial diffuse oxygen supply method under the human day activity state in combination with the actual oxygen demand evaluation of the human body in the local space.The characteristics and the local diffuse oxygen supply method and the oxygen enrichment effect under the indoor sleep environment is rarely involved in the research.Based on this,this paper proposes a local diffusion oxygen supply method,which can be divided into point source and non-point source local diffusion oxygen supply methods according to the different types of oxygen supply terminals;.Firstly,based on the principle of circular cross-section jet flow in fluid mechanics,the flow characteristics of the local oxygen-enriched gas flow is analyzed and mathematically analyzed,and the main influencing factors of the oxygen-enrichment effect mode under the local dispersion oxygen supply mode of the point and non-point source are obtained;secondly,CFD is adopted.Methods Combine the local diffuse oxygen supply method with the human lying model,set the gas density,diffusion coefficient and other parameters according to the environmental characteristics of the high altitude area,establish a solution model for the local diffuse oxygen supply of the plateau sleep environment,and analyze the local oxygen-enriched flow velocity The distribution of oxygen concentration field,oxygen concentration field,and carbon dioxide concentration field;set up a sleep partial oxygen supply experimental platform on the plateau,and arrange oxygen concentration monitoring points to analyze the changes in oxygen concentration over time and space during the experiment and compare with the numerical simulation results.The rationality of the model.In the study,a number of indicators for evaluating local oxygen environment and wind environment were put forward and analyzed.The main research results show the following:(1)This study analyzes the CFD method to explore the velocity distribution of the surrounding airflow when the lying human model inhales,and defines the space for the inhalation area of the lying human body,which is 12 cm long along the direction of the exhaled airflow from the nose,vertical exhale air along nose within a space that is 8cm long horizontally and 4cm high vertically.In this study,the definition of the inhalation area of the sleeping human body lays the foundation for the study of the oxygen enrichment effect of the local diffuse oxygen supply in the sleeping environment.(2)Using the local diffusion oxygen supply method in this study,the oxygen concentration in the inhalation zone increased rapidly from the initial room oxygen concentration and quickly reached the target oxygen concentration value.The average oxygen enrichment rate of the non-point source type was 1.0%/min.The average oxygen enrichment rate of the source type is above 1.5%/min,and the oxygen enrichment rate of the non-point source type is lower than that of the point source type;the oxygen concentration in the point source type suction zone is greatly affected by indoor ventilation,and the ACH is increased from 1 to 3.The maximum fluctuation of oxygen concentration exceeds 1%,while the non-point source type has no major fluctuations;the non-point source type personal oxygen absorption efficiency remains above 95%,which is much higher than that of the point source type.It can be seen that the local oxygen environment created by the non-point source type is higher than that of the point source type.The formula is more reliable.(3)The wind speed can effectively reduce the carbon dioxide concentration in the inhalation zone,and the carbon dioxide concentration in the inhalation zone gradually decreases as the wind speed at the oxygen supply port increases.In a breathing cycle,the concentration of carbon dioxide in the point source and non-point source inhalation zone rises first and then drops rapidly during the expiration phase,drops below 1000 ppm during the inhalation phase,and finally tends to 0 ppm,so there is no need to worry about the accumulation of carbon dioxide.Problem: When the facial comfort speed ratio is greater than 60% and the blowing sensation does not exceed 10%,the best oxygen supply wind speed range for point source type is1.41m/s-3.30m/s,and surface source type is 0.20m/s-0.30m/s,the point source oxygen supply wind speed can be adjusted more widely and the local wind environment created is better.(4)The point source type oxygen supply distance is longer than the area source type,and it needs to maintain a higher outlet wind speed and outlet oxygen concentration.Therefore,a larger oxygen supply is required,and its oxygen supply energy consumption is larger than that of the area source type.Compared with the traditional split oxygen air conditioner for diffuse oxygen supply,the energy consumption of the traditional oxygen-enriched mode is several times higher than that of the point source and non-point source.In practical applications,if a point source or a non-point source is used for local diffuse supply,The oxygen method is more excellent.According to the different types of oxygen supply terminals,this research proposes point source and non-point source local diffusion oxygen supply methods,and analyzes the flow characteristics of local oxygen-rich flow;Defines the inhalation area of the sleeping human lying model through the CFD method;Oxygen efficiency,uniformity,stability and human comfort are comprehensively analyzed in terms of sleeping oxygen environment and wind environment;combined with the analysis of energy consumption of local diffuse oxygen supply,it is determined that the local diffuse oxygen supply method is more economical and suitable,and the high altitude is proposed.The local diffusion oxygen supply strategy can help provide an effective energy-saving method for the sustainable development of buildings in high-altitude areas.