Calculation Method for Heat Transfer Coefficient of Urban Rail Transit Aluminum-alloy Vehicle Enclosure Structure Based on Thermal Resistance Model

Abstract

Objective According to the characteristics of urban rail transit aluminum-alloy vehicle enclosure structure，a K-value calculation method based on thermal resistance model is studied, thereby improving calculation accuracy and efficiency. Method The above enclosure structure is divided into three tiers, with an enclosure structure thermal resistance model established according to the series and parallel relationships of thermal resistances. The series thermal resistance in the third tier includes convective resistance, carbody resistance, and insulation material resistance, as well as a ′simplified resistance′ that can equivalently replace all other thermal resistances along the heat transfer path. By determining the four aforementioned thermal resistances through theoretical calculations and experimental calibration, the total thermal resistance of the enclosure structure can be calculated using the series and parallel relationships of thermal resistances, and subsequently deriving the K-value. Result & Conclusion When compared with experimental results, the calculation accuracy of this method is found to be within 7%. Due to the currently limited availability of K-value experimental data, it is necessary to continually accumulate data and calibrate this thermal resistance model to continuously enhance the accuracy of K-value calculations. An application based on this method is also developed to improve calculation efficiency.

Keywords

• urban rail transit
• aluminum-alloy vehicle
• enclosure structure
• thermal resistance model
• heat transfer coefficient