In this paper the existing CDO procedures at three relevant German airports are analyzed with respect to both the achievable (maximum specific range) and the effectively achieved fuel savings in comparison to conventionally flown arrivals. To do so, we applied our highly precise flight performance model EJPM [1] to several thousand flown trajectories before and after CDO implementation, the data of which was provided to us as radar track data. A technique was developed to estimate the individual aircraft gross mass for calculating the optimum rate of descent starting from the computed flight-specific Top of Descent (ToD). Furthermore, we considered 3D weather and wind data to determine the CDO trajectory. When locating the trajectories within typical ICAO CDO procedure corridors, we found that the current, generic design criteria does not allow the fuel saving potential of CDO to be utilized. Often because of poor CDO execution from the ground and flight deck, only selected aircraft types managed to maintain the defined boundaries. To gain insight on how much detailed procedure guidance is required, a comprehensive weather and aircraft mass sensitivity analysis is also presented. We found analytic models to improve CDO procedures based on local traffic and meteorological conditions, which should supplement current guidance material.
The two types of supercharging processes, either with turbocharger or with mechanically driven compressor are the two systems known to be used on diesel engines for submarines. Each of these two systems has its own limitations.
A two stage supercharging system has been investigated and developed by S.E.M.T. Pielstick. This system is based on a turbocharger used as a low-pressure stage combined with a high-pressure stage compressor which is mechanically driven by the engine.
Test bench results are compared with those obtained with the classical systems.
The new system with two-stage compression has an advantage particularly for the following main points:
- specific power,
- air and fuel specific consumptions,
- capability to sustain high exhaust back pressures as well as low suction pressures and low sensitivity to their fluctuations,
- safety against engine stalling in case of loss of submersion control.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.