Determining the speed of sound, density and bulk modulus of rapeseed oil, biodiesel and diesel fuel

Abstract

Modern tendencies in the development of diesel engines include the operation of the system for injecting diesel fuel at pressures higher than 100 MPa. Knowing the characteristics of liquid fuels such as speed of sound, bulk modulus and density depending on pressure, is important for predicting the behavior of fuel injection systems for diesel engines and optimization of the same. The paper presents an original method and apparatus (device) for determining the speed of sound and density of fluids depending on the pressures. With this method, values of these characteristics for rapeseed oil, biodiesel and conventional diesel fuel at pressures up to 160 MPa are determined. The method is non-destructive, it can also be applied to higher pressures than 160 MPa, as well as other liquid fluids that are used at high pressure - hydraulic oil, for example

Correlation and prediction of biodiesel density for extended ranges of temperature and pressure

“…Their biodiesel had practically the same composition of N21 biodiesel, which was also measured up to 35 MPa for temperatures between 293 K and 373 K. Dzida and Prusakiewicz [25] measured density from 263 K up to 373 K at atmospheric pressure and the values at pressures up to 100 MPa in the range (293-318) K were calculated following a numerical procedure proposed by Sun et al [48]. However, the FAMEs profile was not presented, neither by Nikolić et al [23] who made density measurements for rapeseed biodiesel at 293 K and up to 160 MPa and presented density data in graphic form, which for our purpose was useless. Density as a function of temperature at atmospheric pressure for all fuels in the database is plotted in Fig.…”

“…For this reason and taking into account that density is a linear function of temperature with a slight curvature at high pressures [23,27], the equation…”

“…Literature usually reports biodiesel density measurements made close to the ambient temperature (285-295) K and atmospheric pressure [8][9][10][11][12][13][14] and few measurements of this property have been reported in wider temperature ranges [15][16][17][18][19][20]. The inclusion of pressure has been made in the works by Pratas et al [1], Tat and Van Gerpen [2,21,22], Nikolic et al [23], Aparício et al [24], Dzida and Prusakiewicz [25], and recently by Chhetri and Watts [26] and Schedemann et al [27]. Since density depends on the used raw material from which biodiesel was produced, FAMEs profile is crucial for applying the correlation and prediction models to that property, which also has not been provided by authors [23][24][25].…”

“…The inclusion of pressure has been made in the works by Pratas et al [1], Tat and Van Gerpen [2,21,22], Nikolic et al [23], Aparício et al [24], Dzida and Prusakiewicz [25], and recently by Chhetri and Watts [26] and Schedemann et al [27]. Since density depends on the used raw material from which biodiesel was produced, FAMEs profile is crucial for applying the correlation and prediction models to that property, which also has not been provided by authors [23][24][25].…”

Function K - As a Link Between Fuel Flow Velocity and Fuel Pressure, Depending on the Type of Fuel

“…The method and technique of determining the speed of sound, density and bulk modulus are based on the principle of constant volume and variable mass and density of the fluid in the high pressure part of the installation [38,39]. The examined fluid (in a vessel with a constant volume -high pressure vessel, HPV) compresses when a controlled fluid mass is pumped.…”