Calculation method of high-speed airflow friction coefficient based on strain

Abstract

The invention discloses a strain-based high-speed air friction coefficient calculation method, which comprises the steps of (1) testing axial strain of a test tube; (2) calculating axial deformation of the test tube; (3) calculating high-speed air friction force; and (4) calculating a friction coefficient, namely calculating the friction force of high-speed air on the inner wall of a tubular column by measuring axial strain deformation of the tubular column with consideration on the influences of inner pressure and section change on axial deformation and further calculating the friction coefficient, thereby improving the design applicability and reliability of the tubular column. The influences of an air flow state change and the roughness of the tube wall do not need to be considered.

Description

technical field [0001] The invention belongs to the technical field of drilling, and relates to a strain-based high-speed airflow friction coefficient calculation method. Background technique [0002] The calculation of the friction effect in the design of the injection-production gas string involves the selection of the friction coefficient. The friction coefficient used in the past is mainly obtained from the liquid flow test or the empirical value, which is lacking in the accurate calculation of the friction resistance under the gas flow. Through a large number of investigations and literature review, it is found that in the field of scientific research and engineering practice, there are few research or test results on the friction resistance of gas well strings under the action of high-speed gas flow. Computational studies of resistance have not yet been carried out. Accurate gas-wall friction coefficient must be obtained on the premise of carrying out these studies, w...

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Problems solved by technology

[0005] The main problems in the prior art: 1) The liquid-wall friction coefficient measurement method is the main method, and the gas-wall friction coefficient measurement method is lacking; 2) The friction coefficient in the calculation of the frictional resistance of the gas flow in the gas well string to the pipe string The value is the liquid-wall friction coefficient or empirical value; 3) There are too many interference factors in the determination of the liquid-wall friction coefficient

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