Dealing with hydrogen jets another fundamental issue is to understand if the high density ratio that characterizes such jets affects the mixing properties in terms of spreading rate. 75 MPa, 50 MPa and 25 MPa, issuing into nitrogen at 5 MPa, shows that the use of real gas equations of state affects significantly the jet structure in terms of temperature, pressure and Mach number profiles along the jet centerline and also in terms of jet exit conditions, with differences up to 38 %. The analysis of highly underexpanded hydrogen jets with three different values of total pressure, i.e. To take into account the effects of real gases, both van der Waals and Redlich-Kwong equations of state have been implemented. Besides, the Mach disk structure of underexpanded jets has been recov- ered, thus confirming the suitability and reliability of the computational model. The flow model has been assessed by comparing spreading and centerline property decay rates of subsonic jets at different Mach numbers with those obtained by both theoretical considerations and experimental measurements. An axial symmetric turbulent flow model, which solves the Favre-averaged Navier-Stokes equations for a multicomponent gas mixture, has been implemented and validated. The answer to this question is needed in order to guarantee accurate numerical simulations of such jets in practical engineering applications, such as direct-injection hydrogen engines. The first aim is to untangle the question whether it is necessary to include the real gas assumption dealing with hydrogen jets.

This work examines fundamental problems related to the fluid dynamic structure of turbulent compressible hydrogen jets by using High Performance Computing (HPC) methodologies. Therefore, a comprehensive study of hydrogen jets is needed both to evaluate the feasibility of such engines and to provide guidance for the development of new strategies in order to improve their performance and efficiency. These drawbacks can be overcome by using the direct-injection strategy.

However, hydrogen properties determine some drawbacks when used in ICEs. Certainly, it is believed that the simplest employment of hydrogen is as a fuel into internal combustion engines (ICEs) due to the enormous experience that ICEs technology has gained in the last century. Hydrogen is a very promising alternative fuel for road transport sector in order to reduce emissions of carbon dioxide and other pollutants which are increasingly affecting the health of the planet and citizens.

System mechanic pro 12.7.0.39