The Adiabatic Bulk Modulus of Normal Paraffin Hydrocarbons From Hexane to Hexadecane

Rolling, R. E.; Vogt, Carolin

doi:10.1115/1.3662684

Cited by 19 publications

(11 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Published data for the speed of sound of n-paraffins indicates that longer-chain paraffins have higher speeds of sound than shorter-chain paraffins (11). Therefore, biodiesel, with carbon chain lengths of 17-19 would be expected to have a higher speed of sound than No.…”

Section: Resultsmentioning

confidence: 99%

The speed of sound and isentropic bulk modulus of biodiesel at 21°C from atmospheric pressure to 35 MPa

Tat

Gerpen

Soylu

et al. 2000

J Americ Oil Chem Soc

193

106

View full text Add to dashboard Cite

Biodiesel, an alternative diesel fuel consisting of the alkyl monoesters of fatty acids from vegetable oils and animal fats, can be used in existing diesel engines without modification. However, property changes associated with the differences in chemical structure between biodiesel and petroleumbased diesel fuel may change the engine's injection timing. These injection timing changes can change the exhaust emissions and performance from the optimized settings chosen by the engine manufacturer. This study presents the results of measurements of the speed of sound and the isentropic bulk modulus for methyl and ethyl esters of fatty acids from soybean oil and compares them with No. 1 and No. 2 diesel fuel. Data are presented at 21 ± 1°C and for pressures from atmospheric to 34.74 MPa. The results indicate that the speed of sound and bulk modulus of the monoesters of soybean oil are higher than those for diesel fuel and these can cause changes in the fuel injection timing of diesel engines. Linear equations were used to fit the data as a function of pressure, and the correlation constants are given.Biodiesel has come to be defined as the alkyl monoesters of fatty acids from vegetable oils or animal fats. It can be used as an alternative fuel for diesel engines. Many researchers have reported that oxides of nitrogen (NOx) increase, and particulate matter, carbon monoxide, and unburned hydrocarbons decrease when biodiesel is used in heavy-duty diesel engines (1,2). The reason for the higher NOx emissions is not currently understood but could be due to changes in the chemical composition and the physical properties of the fuel. A major difference between petroleum-based diesel fuel and biodiesel is the 10-11% oxygen content of the biodiesel. The oxygen could change the stoichiometry of the combustion process in a way that produces more NOx. Biodiesel also generally has a higher cetane number than petroleum-based diesel fuel. The cetane number is a diesel fuel property that quantifies the fuel's readiness to autoignite. Higher cetane number corresponds to a shorter ignition delay after the fuel is injected into the cylinder. This results in earlier combustion timing, which tends to increase NOx, and less of the fuel participating in the rapid combustion of the fuel that has premixed during the ignition delay period, which will reduce NOx. These two effects partially offset each other, but higher cetane number in petroleum-based diesel fuels is generally observed to reduce NOx (3). The contribution of biodiesel's higher cetane number to NOx production is still not understood. Changes in physical properties such as viscosity, speed of sound, and bulk modulus also may contribute to higher NOx levels. Injection system anomalies, such as longer injection duration, higher injection pressure, and early injection have been reported by other researchers (4-6).Diesel engines operate by compressing fuel to a high pressure and injecting it into the cylinder where the fuel spontaneously ignites. The fuel is compressed with a piston ...

show abstract

Section: Resultsmentioning

confidence: 99%

The speed of sound and isentropic bulk modulus of biodiesel at 21°C from atmospheric pressure to 35 MPa

Tat

Gerpen

Soylu

et al. 2000

J Americ Oil Chem Soc

193

106

View full text Add to dashboard Cite

show abstract

“…In this research, speed of sound and density were measured in the 30 fuel samples listed in Table 1 from atmospheric pressure to 32.5 MPa and at temperatures of 20, 40, 60, 80, and 100°C. The isentropic bulk modulus was calculated at each pressure and temperature level using Equation 1 (7,8),…”

mentioning

confidence: 99%

Speed of sound and isentropic bulk modulus of alkyl monoesters at elevated temperatures and pressures

Tat

Gerpen

2003

J Americ Oil Chem Soc

View full text Add to dashboard Cite

Biodiesel is a biodegradable, sulfur-free, oxygenated, and renewable alternative diesel fuel consisting of the alkyl monoesters of FA from vegetable oils and animal fats. Biodiesel can be used in existing diesel engines without significant modifications. However, differences in physical properties between biodiesel and petroleum-based diesel fuel may change the engine's fuel injection timing and combustion characteristics. These altered physical and chemical properties also may cause the exhaust emissions and performance to differ from the optimized settings chosen by the engine manufacturer. In particular, the density, speed of sound, and isentropic bulk modulus have a significant effect on the fuel injection system and combustion. The objective of this study was to measure these three properties for biodiesel (and the pure esters that are the constituents of biodiesel) at temperatures from 20 to 100°C and at pressures from atmospheric to 32.5 MPa. Ten different biodiesel fuels, 16 different pure FA esters, three hydrocarbons, and one diesel fuel were tested. The measured values of density, speed of sound, and isentropic bulk modulus are presented. Correlations between pressure and temperature are demonstrated. Speed of sound and isentropic bulk modulus tend to increase as the degree of unsaturation increases and as the chain length increases. However, density increased with shorter chain length and decreased with saturation.Biodiesel, an alternative diesel fuel consisting of the alkyl monoesters of FA from vegetable oils and animal fats, can be used in existing diesel engines without modifications. However, differences in physical properties between biodiesel and petroleumbased diesel fuel may change the engine's injection timing and combustion delay, thus altering the combustion timing and combustion rate. The combustion timing changes can cause exhaust emissions and performance different from the optimized settings chosen by the engine manufacturer. The properties that will have the greatest effect on the fuel injection timing are the speed of sound, the isentropic bulk modulus, and the viscosity. Monyem et al.(1) showed that for fixed injection-pump timing, the injection pressure pulse for biodiesel was 1.5-2.0°advanced from the diesel fuel baseline. The injection timing advance was at least partially due to differences in the fuel properties, such as the bulk modulus and speed of sound. Additional work on the same engine showed that changes in the pump static timing associated with the injection of the greater fuel volume needed to compensate for biodiesel's lower energy content are also responsible for the injection timing advance. The higher viscosity, higher cetane number, and lower volatility of the biodiesel combine with the earlier injection timing to effect the start of combustion. Since emissions of nitrogen oxides (NO x ) generally increase with advanced timing, this effect may be partly responsible for the increase in NO x observed with biodiesel (2-6).The objective of the current project was to m...

show abstract

“…2 diesel fuels were prepared and measured from atmospheric pressure to 32.46 MPa and at temperatures of 20 and 40 °C. The isentropic bulk modulus, which is the inverse of compressibility, was also calculated at each pressure and temperature level using Equation 1 (Boelhouwer, 1967;Rolling and Vogt, 1960).…”

Section: Methodsmentioning

confidence: 99%

Physical Properties and Composition Detection of Biodiesel-diesel Fuel Blends

Tat¹,

Gerpen²

2002

2002 Chicago, IL July 28-31, 2002

View full text Add to dashboard Cite

Biodiesel is an oxygenated, sulfur-free, biodegradable, non-toxic, and environmentally friendly alternative diesel fuel. Biodiesel can be derived from renewable resources, such as vegetable oils, animal fats, and waste restaurant greases. One of the attractive characteristics of biodiesel is that its use does not require any significant modifications to the diesel engine, so the engine does not have to be dedicated for biodiesel. However, due to its different properties, biodiesel will cause some changes in the engine performance and emissions including lower power and higher oxides of nitrogen. Biodiesel can be blended in any proportion with petroleum-based diesel fuel and the impact of the changes is usually proportional to the fraction of biodiesel being used. If the biodiesel-diesel fuel blend level were known, these changes could be eliminated by the engine's electronic control system. The objective of this study was the investigation of the effect of biodiesel blend level on density, speed of sound, and isentropic bulk modulus at higher pressures, and at 20 °C and 40 °C. Also, blend detection with a commercial fuel composition sensor, and the effect of temperature, water, and alcohol on this detection was investigated.

show abstract

The Adiabatic Bulk Modulus of Normal Paraffin Hydrocarbons From Hexane to Hexadecane

Cited by 19 publications

References 0 publications

The speed of sound and isentropic bulk modulus of biodiesel at 21°C from atmospheric pressure to 35 MPa

The speed of sound and isentropic bulk modulus of biodiesel at 21°C from atmospheric pressure to 35 MPa

Speed of sound and isentropic bulk modulus of alkyl monoesters at elevated temperatures and pressures

Physical Properties and Composition Detection of Biodiesel-diesel Fuel Blends

Contact Info

Product

Resources

About