Nitrogen In Tubes Research Articles

Design and Traction Power Calculation of Non-interval Drag Pipe Nitrogen Injection for Fire Control

Aiming at the problems of traditional buried tube nitrogen injection that the nitrogen injection spot with intervals in the space causes the failure of continuous nitrogen distribution in goaf, leading to poor inert effect, in addition, the un-recycling of the nitrogen injection pipe causes much resource waste. The nitrogen injection pipe material is always brittle, of which shear performance is better than its tensile performance. Based on this principle, new fire nitrogen injection process (rotating traction and non-interval) is designed, fundamentally solving major defects of buried tube nitrogen injection, which can realize the synchronous movement between nitrogen injection point and the workface. According to the unloading arch principle and the dynamic calculation of trenchless pipe directional crossing technology, the traction power of non-interval drag pipe nitrogen injection for fire control can be calculated and analyzed. By using a geotechnical engineering numerical simulation software, the stress distribution is simulated for the nitrogen injection pipe in the goaf of YAN ZI SHAN mine, and the traction power is calculated based on it, which lays foundation on successful fulfilments of non-interval nitrogen injection for fire control.

Specific Features of Heat Transfer in the Dispersed Mode of Film Boiling of Liquid Nitrogen in Tubes

Specific Features of Heat Transfer in the Dispersed Mode of Film Boiling of Liquid Nitrogen in Tubes

Anomalous Behavior of Heat Transfer in Film Boiling of Liquid Nitrogen in Tubes at Large Subcoolings and Mass Flow Velocities

Anomalous Behavior of Heat Transfer in Film Boiling of Liquid Nitrogen in Tubes at Large Subcoolings and Mass Flow Velocities

Dispersed flow film boiling of nitrogen with swirl flow

The heat-transfer characteristics of two-phase film boiling of nitrogen in tubes with tape-generated swirl flow are described. The swirl flow substantially augments the heat transfer and minimizes the thermal non-equilibrium, which is responsible for the relatively poor performance of boilers without twisted-tape inserts. Assuming thermal equilibrium, it is possible to formulate a relatively simple superposition correlation for both evaporation and superheat regions of the once-through boiler. The correlation gives good prediction of wall temperatures along the tube for the entire range of test conditions.