Fluorochem (United States)

The dynamic viscosity and density measurements for mixtures of synthetic polyol ester (POE) lubricating oil (ISO VG 32) saturated with compressed 1,1,1,2-tetrafluoroethane (R-134a), pentafluoroethane (R-125), and difluoromethane (R-32) were conducted over a wide temperature range (248.15 K, 273.15 K, 323.15 K, and 348.15 K) and pressures up to 1.0 MPa. The viscosity and density data ranged from 2845 to 6 mPa·s and 1019 to 948 kg·m–3, respectively. Previously reported vapor–liquid equilibrium and modeling data were used to predict the liquid composition for both viscosity and density as a function of temperature and pressure. Redlich–Kister expansions were used to correlate the measured viscosity and density for each HFC/lubricating oil system. Experimental and modeling data were used to calculate the kinematic viscosities and generate Daniel plots.

An efficient 2-furyl gold–carbene promoted synthetic method was developed for the formation of dihydroquinazolinones from enynones by dual insertion of anthranilamides. In this organic transformation a new C–O and two C–N bond formations occurred and dihydroquinazolinones were obtained with a quaternary centre in moderate to very good yields in one-pot synthesis.

Fan noise transmission through and radiation from realistic lined intakes is computed via the GFD method. The high accuracy of this wave-based discretization method and the use of an ”exact” radiation condition supplied by an integral formulation enable genuine 3D simulations at fan-radius Helmholtz numbers up to 22, within practical times on single processor platforms. Helmholtz numbers of 50 can be achieved on a 10-CPUs parallel platform within equivalent computational times. Both axisymmetric and negatively scarfed configurations are considered. For the scarfed case, the effect of axial and circumferential segmentations of the acoustic treatment on the sound radiation is explored at a given frequency and spinning mode order. It is shown that the presence of rigid splices reduces the attenuation effect of the acoustic treatment. Futhermore, the effect of the scarf angle on the upward/downward peak-levels observed for a rigid-wall configuration is no more evident when a segmented liner is considered.

Aeroacoustic simulations of a realistic engine cooling fan system are presented. The rotor/stator interaction flow is modelled via unsteady Reynolds-averaged Navier-Stokes equations. Well converged periodic flow fluctuations are achieved, even in the blade tip region that is the most unsteady area in the fan system. The transient aerodynamic data are used to perform tonal noise predictions via an integral solution of the Ffowcs-Williams & Hawkings equation. The interaction between the rotor-wake and the stator blades is shown to be the dominant sound generation mechanism. Broadband noise computations are performed by using a semi-empirical model of the wall pressure field based on a bivariate normal density distribution of random fluctuations. The statistical model is calibrated on simple heuristic assumptions and recent experimental data collected on the Controlled Diusion airfoil used for the actual fan system, but it has to be improved in order to better recover experimental and advanced numerical data. Finally, as a first step towards a full vibro-aero-acoustic analysis of automotive integrated systems, acoustic harmonics generated by the cooling device are propagated into a bounded domain via a dierential solution of the Helmholtz equation.

In order to evaluate the migration characteristics of insulating gases and vapors, a method was developed to study the permeation characteristics of the blowing agents through films made from the same materials used to make foams. This paper describes a method for measuring the permeation characteristics through films that represent the foam polymer and summarizes data on the permeation characteristics for two polyisocyanurate polymers. These films are made by using commercial formulations without blowing agents. The blowing agents evaluated were: HCFC-22, HCFC-123, HCFC-141b, HFC-134a, HFC-152a, nitrogen (as an air model), and CFC-11 as a control

The use of perfluorocarbon (PFC) fluids such as perfluorinated alkanes and alkylamines as inert medium for organic reactions is demonstrated with advantages summarized. PFC fluids have been found to be very useful in organic reactions where a medium is needed for refluxing and for separating a low boiling component, or where an extremely nonpolar/inert medium is required for reactions carried out under vigorous conditions. The PFC fluids are not miscible with most organic compounds and therefore offer good separatory properties that common organic solvents do not have.

Characterization and determination of the impurities present in 1,1,1,2-tetrafluoroethane (HFC-134a) is critically important to the authenticity of toxicological test results and to the evaluation of HFC-134a as a suitable refrigerant for replacement of primarily Freon 12. Following impurity identification by molecular spectroscopic techniques, two gas chromatographic methods, one capillary and the other a combination packed column with flame ionization detection (FID), have been developed and are used to monitor the purity of HFC-134a samples prepared from various starting materials primarily for use in the Program for Alternative Fluorocarbon Toxicity Testing (PAFTT)-related toxicity studies. A sampling and calibration technique has been implemented and found suitable for a gaseous product containing volatile impurities with a comparatively wide range of boiling points. Carbon number substituent effects were estimated and are used to determine the amounts of impurities present for which pure compounds are not available.