Experimental Characterization of the Thermodynamic Properties of Diesel Fuels Over a Wide Range of Pressures and Temperatures

Energy Conversion and Management

Carreres

Morena

et al. 2018

Section: Fuel Properties Determinationmentioning

confidence: 99%

Section: Fuel Properties Determinationmentioning

confidence: 99%

Computational assessment of temperature variations through calibrated orifices subjected to high pressure drops: Application to diesel injection nozzles

Energy Conversion and Management

Carreres

Morena

et al. 2018

“…Knowing the distance between these two transducers, it is possible to characterize the speed of sound by measuring the time lapse that the pressure perturbation takes to travel to one sensor to another. More information about the experimental setup can be seen in [45]. Figure 2 shows the results from the fuel characterization for a range of 0.1-300 MPa in pressure and 300-400 K in temperature, which are representative of the usage of diesel fuel in advanced common rail systems.…”

Section: Fuel Properties Characterizationmentioning

confidence: 99%

Assessment of compressibility effects on internal nozzle flow in diesel injectors at very high injection pressures

Energy Conversion and Management

Morena

Martinez-Lopez

et al. 2017

Diesel fuel injection systems are being used at higher injection pressure conditions over time because of more stringent emissions requirements. Thus, the importance to properly take into account the fluid compressibility on injection CFD simulations is also increasing. In this paper, an investigation of the compressibility effects in nozzle flow simulations has been carried out for injection pressures up to 250 MPa. To do so, the fluid properties (including density, viscosity and speed of sound) have been measured in a wide range of boundary conditions. These measurements have allowed to obtain correlations for the fluid properties as a function of pressure and temperature. Then, these equations have been incorporated to a CFD solver to take into account the variation of the fluid properties with the pressure changes along the computational domain. The results from

“…3highlighted the need of knowing the evolution of ρ, b and c p with respect to the pressure and temperature in order to determine the theoretical temperature change after an isenthalpic expansion. Speed of sound measurements at different pressures and temperatures were carried out in order to determine the density following the procedure already validated by the authors [21] [33]. The thermal expansion coefficient, b, was then determined through Eq.…”

Section: Fuelmentioning

confidence: 99%

Experimental assessment of the fuel heating and the validity of the assumption of adiabatic flow through the internal orifices of a diesel injector

Gimeno

Carreres

2017

Fuel

In this paper an experimental investigation on the heating experienced by the fuel when it expands through the calibrated orifices of a diesel injector is carried out. Five different geometries corresponding to the control orifices of two different commercial common-rail solenoid injectors were tested. An experimental facility was used to impose a continuous flow through the orifices by controlling the pressures both upstream and downstream of the restriction. Fuel temperature was controlled prior to the orifice inlet and measured after the outlet at a location where the flow is already slowed down. Results were compared to the theoretical temperature increase under the assumption of adiabatic flow (i.e. isenthalpic process). The comparison points out that this assumption allows to predict the fuel temperature change in a reasonable way for four of the five geometries as long as the pressure difference across the orifice is high enough. The deviations for low imposed pressure differences and the remaining orifice are explained due to the low Reynolds numbers (i.e. flow velocities) induced in these cases, which significantly increase the residence time of a fuel particle in the duct, thus enabling heat transfer with the surrounding atmosphere. A dimensionless parameter to quantify the proneness of the flow through an orifice to exchange heat with the surroundings has been theoretically derived and calculated for the different geometries tested, allowing to establish a boundary that defines beforehand the conditions from which heat losses to the ambient can be neglected when dealing with the internal flow along a diesel injector.