Multi-objective optimization of the cooling system of a diesel helicopter

CRDID (Common Rail Diesel Engine) main advantage is the extremely high efficiency (up to 52%), the enormous amount of hours run and the flight readiness. Moreover, diesel fuel is safer than jet fuel and it is available everywhere. Therefore, refuelling flights to airports or dedicated supply lines can be avoided. However, diesel engines are generally heavier than turboshafts and require an additional cooling system. This requirement is particularly stringent during near stationary operations of the helicopter. In fact, if fans are used for the cooling system, the available power is reduced with an increased penalty weight for the installation. For this reason the ejector exhaust system can be successfully used in CRDID powered helicopters. A feasibility study of the cooling system for a CRDID (Common Rail Diesel Engine) on a common light helicopter (Eurocopter EC 120-class) is introduced. Optimization of this system is performed. The total mass available for the CRDID is evaluated starting from fuel consumption and helicopter data. A derivative of an automotive engine is proposed for the turboshaft replacement. The result is that the ejector exhaust (augmenter) is extremely effective. Solid Works Flow Simulation confirms the ejector choice and the design criteria.