Effect Of Oil Contamination Research Articles

Condensation of R-410A in a Rectangular Channel

A two-phase loop to measure the condensation heat transfer coefficient of R-410A was designed, built, and calibrated. The test section was a 3 m (10 ft) long horizontal, rectangular brass (63% Cu, 37% Zn by mass) tube 12.7 mm (0.5 in.) wide and 25.4 mm (1.0 in.) high. Uncertainty analysis was performed for each set of collected data. Any experimental data with an uncertainty greater than 10% was discarded. Also, any experimental data that failed to satisfy the energy balance for the test section within 5% was discarded. Over three hundred experimental runs were made. They covered a mass flux range of 30 to 200 kg/(s·m2) (2.2×104 to 1.48×105 lbm/h·ft2), a refrigerant saturation temperature range of 7.8 to 36.7°C (46 to 98°F), and a saturation pressure range of 1.02 to 2.23 MPa (147.4 to 323.4 psi). From this experimental database, 173 sets of data, which satisfied both the heat balance requirement and uncertainty requirement, were selected for further analysis. This study focused primarily on measurement and prediction of condensation heat transfer coefficients and the relationship between heat transfer coefficients and two-phase flow regimes. Flow pattern studies showed that the condensation was predominantly in the wavy stratified flow regime at a mass flux of less than 200 kg/(s·m2). For higher mass flux rates, the condensation was in the annular flow regime. The regionally averaged heat transfer coefficient for condensing R-410A in a rectangular channel decreased with a decrease in quality, and increased with an increase in mass flux. Using the experimental database a correlation was developed to predict the regionally averaged condensation heat transfer coefficient. In the same experimental study, the effect of oil contamination on the heat transfer performance of condensing R-410A was also investigated. Tests were conducted with two different oil concentrations (1.26% and 2.51% by mass). Results indicated that the presence of oil decreased the condensation heat transfer coefficient by 10 to 20%.

Bearing capacity of a model scale footing on crude oil-contaminated sand

Onshore and offshore oil spills contaminate soil. In addition to environmental concerns for ground water pollution and other possible effects, the geotechnical properties of the contaminated soil such as the shear strength and the hydraulic conductivity are also altered. This note is a report of research in progress to evaluate the variation of the shear strength of a sand contaminated by a crude oil and thus the ultimate bearing capacity of shallow foundations. The limited results of the tests reported here relate to only one type of sand and one crude oil. The oil content was varied from zero to 4.2%. Results of direct shear tests for determining the soil friction angle are given. Along with these, laboratory model test results for the ultimate bearing capacity of a surface strip foundation supported by crude oil-contaminated sand are also presented. Based on these test results, the effect of oil contamination in drastically reducing the bearing capacity is discussed.

The effects of cold temperatures and crude oil on the abundance and activity of protozoa in a garden soil

The abundance and number of protozoan species inhabiting garden loam soil were monitored throughout the winter of 1979–1980 in both undisturbed and crude oil polluted sites. The effect of oil contamination on protozoan colonization was investigated using autoclaved soil cores. Oil did not appear to affect seriously either the encysted or trophic protozoa. Encystment was rapid at temperatures above 0 °C, and the evidence suggests that the soil protozoan population was active for short periods on many occasions throughout the winter.