Liquid-liquid equilibria for the system perfluorodecalin/1-heptene/n-heptane/n-hexane

Liquid-liquid equilibria for the quaternary system perfluorodecalln (PFD)/l-hepteneln-heptaneln-hexane at 288.15 K (type 111) and 298.15 K (type 11) and for the ternary systems PFDII-hepteneln-heptane, PFDII-hepteneln-hexane, and PFD/n -heptane/n-hexane at the same temperatures are reported. The experimental results are compared with values predicted by using the NRTL, the UNIQUAC, and the UNIFAC models

Some difficulties on the application of the UNIFAC model for the prediction of liquid-liquid equilibrium compositions

UNIFAC group parameters for the interaction between CH2 and CF2 (c) and CH2 and CF3 were obtained using experimental liquid-liquid equilibrium data for hydrocarbon - perfluorodecaline (PFD) and hydrocarbon - perfluoromethylcyclohexane (PFMCH) systems. Some difficulties were experienced on the use of the UNIFAC method with those particular systems, namely the group parameters dependence on the length of the hydrocarbon chain. Attempts were made to correlate UNIFAC parameters with the number of carbon atoms and temperature and the results compared with those obtained with NRTL equations

Liquid-liquid equilibria of systems containing perfluoromethylcyclohexane

Liquidliquid equilibria for the quaternary system perfluoromethylcyclohexane (PFMCH)1-heptenen-heptanen-hexane at 288.15 K and for the ternary systems PFMCH1-heptenen-heptane, PFMCH1-heptenen-hexane and PFMCHn-heptanen-hexane at 279.15 K and 288.15 K are reported. The experimental results are compared with predicted values calculated using the NRTL and the UNIQUAC models

Experimental and Numerical Investigation of Post-Flutter Limit Cycle Oscillations on a Cantilevered Flat Plate

Futuristic aircraft designs and novel aircraft such as High Altitude Long Endurance (HALE) involve a higher level of structural flexibility than in conventional aircraft. Even at present, the trends in the aviation industry are to increase wing length (to reduce induced drag) and maxi- mize use of composites, which lead to increased structural flexibility. This necessitates a rethink of conventional (linear) aeroelastic analysis, since the increased flexibility results in coupling between the flight dynamic and aeroelastic dynamics, and consequently, limit-cycle oscillations of the structure. In this paper, a new three-dimensional low-order model for unsteady aerody- namics that accounts for large oscillation amplitudes and nonplanar wakes is developed. An experiment with a cantilevered flat plate at low Reynolds number is set up and used to validate the low-order model, as well as to study post-flutter limit-cycle oscillations. Results from the low-order model are promising, but show that aerodynamic nonlinearities such as flow sepa- ration and leading-edge vortex shedding must also be modeled in order to predict all possible limit-cycle oscillations of the aeroelastic system

Perfluorodecalin/hydrocarbon systems prediction and correlation of liquid-liquid equilibrium data

Experimental binary, ternary and quaternary liquid-liquid equilibrium data for systems containing perfluorodecaline (PFD) and some hydrocarbons were determined. Binary NRTL, UNIQUAC and UNIFAC parameters were obtained, from the binary, the ternary and the quaternary experimental data: for the calculation of parameters from binary data a Newton-Raphson technique was used and the parameters so obtainedfor each temperature (T)-were linearly correlated with T and 1/T. Predicted binary, ternary and quaternary data were then compared with the experimental results; a Nelder-Mead method was used for the calculation of the binary parameters from ternary tie-line data. UNIFAC group parameters for the interaction CH2/CF2 and CH=CH2/CF2 were obtained. Attempts were made, and are discussed, to: correlate UNIFAC parameters with the number of carbon atoms and temperature; obtain a set of NRTL and UNIQUAC parameters yielding the overall best fit for the systems under consideration

Mutual binary solubilities: perfluoromethylcyclohexane-hydrocarbons

Mutual binary solubility data for perfluoromethylcyclohexane+n-hexane, n-heptane, n-octane, n-nonane, 1-hexene and 1-heptene are reported. NRTL and UNIQUAC parameters, for each experimental temperature, were obtained using a NewtonRaphson technique and the parameters so obtained were linearly correlated with T and T1. UNIFAC group parameters for the interaction CH2/CF3 and CH=CH2/CF3 were obtained from mutual solubility data using the same technique. UNIFAC parameters were correlated with the number of carbon atoms and temperature

Mutual binary solubilities: perfluorodecalin/hydrocarbons

Mutual solublllty data for perfluorodecalln + n-hexane, + n-heptane, + noctane, + n-nonane, + 1-hexene, and + 1-heptene are reported. The NRTL and UNIOUAC equatlons were used to correlate the data. UNIFAC group parameters for the lnteractlons CH2/CF,( c) and CH=CHJCF,(c) can also be obtained