Experimental investigation of pressure drop in helical coils.

Abstract

The purpose of this study was to begin an investigation of the pressure drop in flow through helical coils. in general, the procedure followed was to define the governing parameters and then to isolate the effect of each on the pressure drop. The pressure drop was assumed to depend on the length of the tube, the inside diameter of the tube, the diameter of the helix, the roughness of the inside of the tube, and Reynolds number. Variation of pressure drop with change in diameter of the tube was not investigated. Five different lengths of plastic tubing were tested separately on five helices of different diameters at Reynolds numbers from 3,000 to 100,000 to study the effects of length and helix diameter. Twelve steel coils of different inside roughness were tested over the same Reynolds number range to obtain the effect of roughness on pressure drop. the results of this investigation indicated that pressure drop in a helical coil is linearly dependent on length, is only slightly affected by roughness, and is a function of both Reynolds number and diameter of helix as indicated in the attached curves. These conclusions, of course, hold only for the limited field covered by the investigation.