A suction line of a refrigeration cycle with vertical upward flow is one area where the refrigeration oil tends to accumulate. This paper discusses the flow characteristics of the oil film in a pipe with the vertical upward flow. Air and oil two-phase flow is used as the first step of the study and the flow pattern of the oil film in the vertical upward flow is observed. The oil film thickness ...

This paper investigates the parametric excitation of a micro-pipe conveying fluid suspended between two symmetric electrodes. Electrostatically actuated micro-pipes may become unstable when the exciting voltage is greater than the pull-in value. It is demonstrated that the parametric excitation of a micro-pipe by periodic (ac) voltages may have a stabilizing effect and permit an increase of the...

in this paper, two api x70 steel pipes (with spiral seam weld) of 56 inch outside diameter and 0.780 inch wall thickness were girth welded first. next, hole drilling tests were conducted for strain measurement on the surfaces of the pipes. the values of residual stresses on the internal and external surfaces of the pipe were determined, from strain data using astm 837 standard. the experimental...

The mechanism of pipe–soil interaction under frost heaving is complicated due to many factors affecting the system. In order analyze sensitivity various influencing and highlight relationship between pipe’s mechanical characteristics during heaving, a model based on semi-infinite elastic frozen soil foundation developed. Besides, indices characterizing influence their change law are emphaticall...

The purpose of this study is to investigate bending moment and the axial load capacity of a pressurized pipe suffering from a through-wall circumferential crack repaired by a composite sleeve. The three-dimensional finite element method (FEM) was adopted to compute the results, and the failure assessment diagram (FAD) was employed to investigate the failure behavior of the repaired pipe. The fi...

thickness and corrosion/erosion rate. In this thesis, a combination of signal processing techniques are used to estimate the corrosion rate estimates based on MBE. Corrosion rate is estimated based on ultrasonic pipe wall thickness data is collected over a short period of time using MBE model. This technique is based on data collected from the speedometer applied for thinning and both indicate ...

In order to achieve integrated condition in the girth welding of high pressure natural gas transmission pipelines, the weld zones and its surrounding area should have good mechanical properties. Residual stresses are an important defect especially in the girth welding of the pipeline. In this study, two API X70 steel pipes (with spiral seam weld) of 56 inches outside diameter and 0.780 inch wal...

Perforation in internal upset transition zone is one of the main failure styles for drill pipes. Due to the flow channel specificity of upset transition zone, in this paper, drill pipe failure analysis from the point of flow erosion was put forward. Flow field of drilling fluid in the internal upset transition zone of U127 mm API IEU S135 drill pipe under various conditions were obtained using ...

The prompt gamma rays emission, following neutron absorptions are characteristics of material under test and its intensity is proportional to amount or thickness of the material. The method is non-contact, and can, therefore, be very useful for scale or corrosion measurement of high temperature or insulated pipes. This method can be used to identify type of scale if it is not known. Neutron fro...