Laminar flow control is next-generation technology which is expected to improve aerodynamic performance greatly. As for an application of laminar flow control in the aircraft design, it is important to consider comprehensive effects of laminar flow control system on design results. In this paper, we include the effects caused by additional laminar flow control system into the aircraft conceptual design tool and consider interactive effects on aerodynamic, propulsion and secondary power systems. Two types of laminar flow control technology have been considered and were applied to 200 passenger class transport aircraft. They are natural laminar flow (NLF) and hybrid laminar flow control (HLFC). Results indicated that NLF can improve lift / drag ratio and fuel consumption, and hence decreases the aircraft empty weight. Applying the HLFC improves lift / drag ratio and fuel consumption further. However, because of the additional weight of HLFC system, the maximum take-off weight of HLFC aircraft is equivalent to that of the NLF.
Research is widely conducted on air-diluted and EGR-diluted combustion of natural gas that contains no sulfur and less carbon. This study focused on a relationship between the laminar burning speed of methane-diluted mixtures and their heat release rate. In order to analyze the laminar burning speed with high accuracy, we measured the temperature of in-cylinder gas using an infrared absorption method. Using the data obtained, the pressure, temperature, and dilution ratio, we constructed a formula to predict the laminar burning speed with high accuracy. It has been experimentally shown that mixtures with nearly laminar burning speed of equivalence ratio and EGR ratio combination and the same ignition timing have the similar heat release rate.