Impact analysis of slope on the head loss of gas-liquid two-phase flow in siphon pipe

Abstract

Through an analysis of the head loss of the gas-liquid two-phase flow in a siphon pipe, this paper measures the bubble velocity, pressure drop, and gas fraction under various conditions. The influence of varied head, gradient, and installation heights of the pipe on the air mass movement, head loss, and resistance coefficient of the gas-liquid two-phrase flow is analyzed on the basis of the test results. The results show that the bubble velocity reaches its minimum on the flat slope, and the velocity on the positive slope is higher than that on the reverse slope. The head loss of pipelines in both the positive slope and reverse slope increases as the gradient increases, while the head loss on the reverse slope is larger than that on the positive slope under the same gradient. When the gas fraction λ is between 8% and 30%, the resistance coefficient λm is related to the gradient, gas fraction, and the Reynolds number Re. Furthermore, λm is proportionate to α; and inversely proportionate to i of the bottom slope and the Re number. The calculation formula of the resistance coefficient λm under various gradients within the scope of the above gas fraction is derived on the basis of the test data, while the relative error is controlled within the allowable range.