Numerical Analysis of Under-expanded Jets for Gas Fuel Injection using OpenFOAM

Makoto Nagaoka･Daiki Shindo･Hiroki Sowa･Kanta Takiguchi (Osaka Sangyo University)

The calculation accuracy of the open CFD software OpenFOAM was validated as a tool for analysing gas jet characteristics for further effective use of gas fuels. The under-expanded jets formed when hydrogen, methane and nitrogen are injected into the atmosphere from a gas fuel injector were compared with visualisation experiments using the Schlieren method. The differences between calculation methods such as flux difference scheme and turbulence models, and jet characteristics depending on gas type were analysed.

Development of a Technology for Predicting Exhaust Airflow Noise during Engine Combustion using a Hybrid Method

Toru Tsurumoto･Kyoji Ishihara･Toshiyuki Hirobe･Osamu Torobu (Mazda)･Naoki Nakamura･Takahiro Shinkawa (HIROTEC)

Due to the recent strengthening of noise regulations, vehicles with internal combustion engines are required to reduce exhaust noise. To improve development efficiency, we have developed a technology that quantitatively predicts the frequency characteristics of airflow noise, which is one of the components of exhaust noise caused by engine combustion and exhaust gas flow, using a hybrid method that combines CFD (Computational Fluid Dynamics) and acoustic analysis.

Development of Prediction Method of Parts Temperature in Idling State and Factor Analysis of Temperature Rise from Heat Source

Yuki Morita･Koichi Ishikawa･Hiroyuki Takamura (Mitsubishi Motors)･Reon Wachi (Mitsubishi Automotive Engineering)･Zongguang Wang (Mitsubishi Motors)

While a vehicle idling, the temperature of vehicle parts rises due to the reduction of travel wind. The idling state is transient because of the temperature drop of exhaust pipe and has complex flow field because of cooling-fan operation. This causes difficult prediction of the maximum temperature of parts in idling state. Thus, the coupled CFD simulation method is developed to predict the maximum temperature of the parts in idling state.
In addition, the method is developed to analyze the factor of temperature rise from exhaust pipe in order to put heat protector to reduce heat damage effectively.