A Study on the Influence of Nacelle Environment on the Cold Gas Passage Temperature Rise of Civil Aircraft Pneumatic System

By employing numerical simulation methods, the heating issues of the pneumatic system’s cold gas passage in hightemperature nacelle environments for civil aircraft were investigated. The research discussed variations in airflow velocity within the nacelle, environmental temperature changes, flow velocity within the cold passage, and the impact of other hightemperature heat sources on raising the temperature of airflow within the cold passage. The results indicate that the higher hot temperature airflow of nacelle environment, the faster airflow velocity in the nacelle, as well as lower cold passage airflow velocity, lead to greater temperature increases within the cold passage. A correlation with constants that satisfy the operating conditions of the pneumatic system was derived by referencing existing empirical correlations for forced convective heat transfer across a single pipe. Further research was conducted on the impact of high-temperature heat sources on the cold passage, the results indicated that under the influence of radiation heat transfer, significant temperature non-uniformity near the wall of the cold passage occurs when the high-temperature equipment near the cold passage exceeds 1000K.