Research on the Heating of Deicing Fluid in a New Reshaped Coiled Tube

Abstract

Aircraft ground deicing operation is significant to ensure civil flight safety in winter. Helically coiled tube is the important heat exchanger in Chinese deicing fluid heating system. In order to improve the deicing efficiency, the research focuses on heat transfer enhancement of deicing fluid in the tube. Based on the field synergy principle, a new reshaped tube (TCHC) is designed by ring-rib convex on the inner wall. Deicing fluid is high viscosity ethylene-glycol-based mixture. Because of the power function relation between high viscosity and temperature, viscosity has a negative influence on heat transfer. The number of ring-ribs and inlet velocity are two key parameters to the heat transfer performance. For both water and ethylene glycol, the outlet temperature rises when the number of ring-ribs increases to a certain limit. However, the increasing of velocity reduces heating time, which results in lower outlet temperature. The heating experiment of the original tube is conducted. The error between experiment and simulation is less than 5%. The outlet temperature of TCHC increases by 3.76%. As a result, TCHC efficiently promotes the coordination of velocity and temperature fields by changing the velocity field. TCHC has enhanced heat transfer of high viscosity deicing fluid.

On Flight Risk Quantitative Evaluation under Icing Conditions

“…(4) Anti-Icing System and Ice Airspace Avoidance. The efficient and effective anti-icing methods [28], accurate prediction, and avoidance meteorology methods of icing airspace [29] were intensively studied and applied to engineering practice. Related institutions increased the rules and procedures.…”

“…Furthermore, in the actual, we only need to select the most sensitive parameters for flight safety Here, 1 ( min ), 2 ( max ), 3 ( max ) are all continuous distribution functions, so Copula is the only one. The commonly used multidimensional Copula models and corresponding generators are shown as (24)- (28).…”

“…represents Joe Copula model based on formula (28). According to the identification results in Table 7, flight risk probability under the above simulation conditions (asymmetric wing icing) is 0.0924.…”