Bernoulli Balance Experiments Using a Venturi

Two simple and inexpensive venturi experiments were developed for use in either the laboratory or classroom.The purpose of this paper is to present the equipment, procedures and experimental results for these experiments, as used in a junior level fluids laboratory.In the first experiment, a shop fabricated venturi was employed to determine the experimental minor loss coefficient, K, in an unsteady-state system.The throat velocity determined by the Bernoulli balance was about 16% higher than the measured experimental velocity.The minor loss coefficient was 0.86, which indicates only about 15% of the energy contained in the throat stream was recovered.This value is consistent with results reported in the literature.In the second experiment, a venturi was fashioned from small, inexpensive funnels and once again used to determine the experimental minor loss coefficient, this time in a steady state system.The average calculated minor loss coefficient was 0.28 and deviated about 3.6% among the three experimental runs.The experimental throat pressures ranged from 26.2-28.5 in Hg absolute, and the theoretical and experimental pressures agreed within 5%.