using the wall-attachment effect in separating two liquids. Two 
experimental elements with different flow parameters were built 
and tested. The experiments were conducted in the Mechanical Systems 
Laboratory at NCEL using a mixture of regular tap water and hydraulic 
oil as the test fluid. 
The Wall Attachment Elements 
Based upon the theory developed in Appendix A, two experimental 
elements, namely, Elements No. 1 and No. 2 were designed. 
The 12-inch-long attachment wall of each element has an offset 
of 4 inches. The nozzles on Elements No. 1 and No. 2 are 1/4 
and 3/8 inches wide respectively. The depth of flow passages 
on both elements is 1/4 inch. Element No. 1 was designed to 
carry 0.8 gpm of water flow whereas Element No. 2 has a flow 
carrying capacity of 1.5 gpm. The jet flow parameters such 
as reattaching distance xp, jet center line radius r and its 
half width yg at the reattachment point were determined from 
Figures A-2 through A-5 given in Appendix A. The jet spread 
parameter, o, for the above calculations was chosen to be 12. 
The dimensions of the elements are listed in Table l. 
Each element consisted of three major components: top 
and bottom cover plates, and the middle plate with the flow 
passages machined in it. For ease of fabrication and to facilitate 
flow visualization during tests, each component plate of the 
Elements was made of transparent plexi-glass sheet. Further, 
to extract the accumulated oil in the separation bubble, a 
1/4 inch diameter outlet was provided in the top cover plate 
of each element. The general layout showing major dimensions 
of the elements is given in Figure 3. The elements were assembled 
by gluing the two cover plates to the middle plate. 
Feasibility Tests 
The experiments were performed using the test setup shown 
in Figure 4. The adjustment of supply water flow is possible 
by hand controlled valves provided on the flow line. A mixture 
of red hydraulic oil (Appendix B) and water was used as the 
test-fluid. The mixture was formed by injecting the oil into 
water stream before it entered the element. To form a homogenous 
mixture, the oil was released at the center of and parallel 
to the water flow in the pipe. The oil to the mixing junction 
was supplied by a variable flow pump (see details in Appendix 
B). The element was immersed in water throughout the test series. 
The supply water flow was measured by a rotameter. The static 
pressure in the water line was measured by conventional pressure 
gauges. The use of red oil in the test mixture allowed flow 
visualization through the elements. The photographs of flow 
patterns were taken by mounting a camera directly above the 
elements. 
The feasibility tests were conducted by running the oil 
