Densities and Viscosities for the Ternary Mixtures of <i>n</i>‑Undecane (1) + Butylcyclohexane (2) + 1‑Pentanol (3) and Corresponding Binaries at <i>T</i> = (293.15 to 333.15) K

The actual composition is known to be highly responsible for the physical and chemical properties of a fuel. To understand the foundational physical properties of an aviation kerosene substitute mixture for hypersonic aircraft, n-undecane, butylcyclohexane, and 1-pentanol were used to construct a ternary system. The values of density (ρ) and viscosity (η) for the ternary system and three corresponding binaries were measured at temperatures T = (293.15 to 333.15) K and pressure p = 0.1 MPa. The Redlich–Kister equation was used to fit the excess molar volumes (VmE) and viscosity deviations (Δη) of the binary systems, while those of the ternary system were correlated with four semi-empirical formulas (Cibulka, Singh, Redlich–Kister, and Nagata–Tamura equations). The experimental results show that the VmE values of the three binary mixtures have a positive relationship with the mole fraction of nonpolar components, while Δη values have a negative relationship. The non-ideal behavior of mixtures is discussed from the perspective of molecular interactions and structural effects. This work provides data support and guidance for fuel compatibility research

Density and Viscosity Measurements on the Ternary System of <i>exo</i>-Tetrahydrodicyclopentadiene (1) + <i>n</i>‑Decane (2) + Iso-Butanol (3) and Corresponding Binary Systems

exo-Tetrahydrodicyclopentadiene can serve as both the propellant and coolant in hypersonic vehicles. However, its applications are restricted by the poor properties of ignition and combustion to some extent. Fuel additives such as appropriate alcohols have the ability to overcome these deficits. Research on thermophysical properties of the mixtures composed of exo-tetrahydrodicyclopentadiene and fuel additives can provide important information for the research of fuel additives. In this work, densities and viscosities of the ternary system of exo-tetrahydrodicyclopentadiene (1) + n-decane (2) + iso-butanol (3) and three corresponding binary systems have been measured over the whole composition range in the temperature range from 293.15 to 333.15 K with an interval of 5 K and at pressure p = 0.1 MPa. The values of excess molar volumes (VmE) and viscosity deviations (Δη) of three binary systems and the ternary system were calculated and then fitted to the Redlich–Kister equation and four semi-empirical equations, respectively. The variations of VmE and Δη were explained from the viewpoints of intermolecular forces and structural effects. Furthermore, the Jouyban–Acree model was used to correlate the values of densities (ρ) and viscosities (η) of the studied mixtures with high accuracy

Strategically Designed Hyperbranched Polyglycerol as an Efficient Integrated Additive for Hydrocarbon Fuels

In this study, palmitoyl and hindered phenolic hyperbranched polyglycerol (CBHPG), with hyperbranched polyglycerol (HPG) as the structural core and hindered phenol or alkyl chain as the decorated shell, has been strategically designed and synthesized as an efficient integrated additive to enhance the energy efficiency and inhibit the oxidation coking of hydrocarbon fuels. The superior thermal stability and solubility of CBHPG were confirmed by thermal gravimetric analysis and dynamic light scattering. In the presence of CBHPG with high antioxidant activity, the oxidation induction time of n-undecane increased more than 2-fold at 170 °C. In deposition tests, the amphiphilic macromolecule CBHPG showed excellent performance with 58% oxidation coking inhibition rate of Chinese Jet Fuel (RP-3). The Jet Fuel Thermal Oxidation Stability test at 355 °C also exhibited that CBHPG could greatly reduce the deposit of RP-3 by decreasing the deposit rating from >4 to <1. In cracking experiments, the addition of 0.1 wt % CBHPG with sufficient polymerization could increase the conversion of n-undecane by 17.6%, with the corresponding heat sink by 6.1% at 675 °C. The above results indicated that CBHPG could efficiently enhance the performance of hydrocarbon fuels due to multipurposes in antioxidation, coking inhibition, and cracking promotion. CBHPG with a strategically designed structure as an integrated additive shows great promise in improving the energy efficiency and safety in future advanced aircraft

Densities and Viscosities of the Ternary Mixtures of Decalin (1) + <i>n</i>‑Hexadecane (2) + 1‑Butanol (3) and Corresponding Binary Systems

Active cooling by endothermic hydrocarbon fuels (EHFs) is considered as a practical approach to deal with the thermal management problem of hypersonic aircrafts. As a typical component of EHFs, decalin is usually thermally stable while it is apt to coke and has poor combustion performance. n-Hexadecane, a normal alkane with a relatively high H/C ratio, can effectively improve the combustion performance of EHFs, and 1-butanol has remarkable anti-coking properties. As a fundamental work for fuel design, decalin, n-hexadecane, and 1-butanol were selected as model compounds to construct a surrogate fuel system, which was used to investigate the effects of composition and condition on its thermophysical properties. Densities (ρ) and viscosities (η) of the ternary system of decalin (1) + n-hexadecane (2) + 1-butanol (3) and corresponding binary systems were measured at temperatures T = (293.15 to 333.15) K and pressure p = 0.1 MPa. The excess molar volumes (VmE) and the viscosity deviations (Δη) of the mixtures were calculated and fitted to several semi-empirical equations. The tendencies of VmE and Δη with composition and temperature were discussed from intermolecular force and molecular size, respectively

Calixarene-Capped Platinum Nanofluid for Pseudohomogeneous Catalytic Cracking and Heat Sink Enhancement of Ethylcyclohexane

To solve the heat management problem of supersonic aircraft, endothermic hydrocarbon fuels (EHFs) have been developed as both a coolant and a propellant. The pseudohomogeneous catalyst is an efficient way to improve the heat sink of EHFs. In this work, hydrocarbon soluble macrocyclic calixarene compound C-undecyl calix[4]2-(propylsulfanylmethyl)-resonrcinarene (C11–SC3) was synthesized and used as a stabilizer for hydrocarbon-dispersed Pt nanoparticles (Pt@C11–SC3). The morphological characterization results indicate that Pt nanoparticles are encapsulated by the calixarene, which helps the fabrication of ultrasmall Pt@C11–SC3. Ethylcyclohexane (ECH) was selected as a model substrate of EHFs to construct the Pt@C11–SC3/ECH nanofluid system for pseudohomogeneous catalytic cracking. The cracking test of the Pt@C11–SC3/ECH nanofluid was carried out in a batch reactor and a flow reactor under constant volume and pressure conditions. The distribution of cracking products displayed a significant improvement in terms of cracking conversion and a preferred heat absorbed reaction pathway, leading to a higher heat sink. There was a 16% maximum increase in heat sink in the constant pressure cracking tests with the addition of 0.01 wt % Pt@C11–SC3 at 700 °C. It provides a helpful method for heat sink enhancement of EHFs