Combined experimental and computational investigations of a device for respiratory organs protection at low air temperatures
Authors: Sinitsyn Anton , Monarkin Nikolay , Sizanova Anna , Derevianko Oleg 
Published: November 2018

Investigation of the Arctic region is a crucial task and comprises various geopolitical, economical, technological and ecological activities at a global scale. In the course of intensification of the geopolitical struggle for resources usage, the Arctic region has now brought under new scrutiny. The known development strategies for the Arctic zone of the Russian Federation are based on the usage of advanced technologies. They are aimed at the creation of supply systems for emergency-rescue and other urgent works at specific severe conditions and critically important objects, including oil and gas production, power and communal facilities. These tasks might be accomplished using modern heat-protective devices, which provide effective and sustainable usage of human energy resources. Among the vast variety of individual safety gear for workers, there are some devices which are highly-efficient at extremely low-temperature conditions. These devices are based on thermal energy regeneration process of the exhaled air. Air temperature under the mask is increased driven by the heat of expired air and heating of incoming cold air while passing through the regenerative heat exchange unit. This heat-exchange unit was previously heated during expiration. This paper presents a survey concerning the following themes: a review of scientific researches, concerning tools for human respiratory organs protection at low air temperatures, patent documents and commercially-viable technical devices used for this purpose, as well as mathematical models of regenerative heat exchange. The devices and methods were compared, their advantages and disadvantages were revealed. It was stated that the most effective heat-exchange device is not that made of tissue material, but that is a solid-state composite construction of an irregular shape with internal channels for air transport. The presented thermal mask cap is designed so that vertically oriented channel rows do not connect with each other. The developed mathematical model is based on Newton-Richmann law. This model includes equations with efficiency coefficients for regenerative cap material at accumulation and regeneration heat stages. For various external air temperatures, we have calculated temperature oscillations between regenerative heat exchange unit input and output. These values were plotted together with the experimental temperature values and compared. Mathematical model adequacy and energy efficiency coefficients for thermal masks were determined. An engineering technique for device efficiency determination was proposed. The conducted combined experimental and computational investigations allowed us to carry out the efficiency analysis of the existing heat-protective masks which are based on thermal energy regeneration process of the exhaled air for inhaled air heating. The numerical values for the efficiency coefficients were obtained, and we made some conclusions concerning further device improvements on behalf of the Arctic region development.