Small-Diameter Tube Wall Damage-Detection Method Based on TE01 Mode Microwave

Abstract

Accidents occur frequently in urban gas pipelines, and pipeline damage detection is an important means of ensuring pipeline safety. Aiming at the problem that the small diameter pipeline is difficult to detect, this paper proposes a detection method for the inner wall damage of a small-diameter pipeline based on the TE01 mode microwave and uses the TE01 mode to detect the inner wall damage of the pipeline by the terminal short-circuit reflection method. By analyzing the transition of microwave propagation mode at the defect, based on the Maxwell equation and the field distribution equation of the TE01 mode microwave in the pipe and the pipe wall current equation, the microwave reflection coefficient at the defect is established when the microwave distortion modes at the defect are TE and TM modes. A small-diameter pipeline simulation model is established, and the influence of the electric field, magnetic field, wall current distribution, and reflected wave reflection coefficient in the pipeline when inner wall defects of different widths are analyzed using the finite integral theory during microwave detection of the TE01 mode. An experimental platform for the microwave detection of small-diameter pipes was built to detect defects on the inner walls of pipes with different widths. The results show that the inner wall defect causes the electric field, magnetic field, current propagation period, and energy distribution of the TE01 mode microwave propagated in the pipe to be distorted, and the microwave reflection coefficient and return loss exhibit a significant frequency shift with the change in the defect width. The experimental and simulation results had a good consistency.

Design of a simple side-incident TE11 mode microwave probe for nondestructive pipe inspection

“…In particular, a back propagation neural network was trained in that study to quantitatively evaluate the depth and length of a wall thinning defect using the extracted resonant frequencies of TM 01 microwave signals and showed good performance. Previous studies have proven the feasibility of this method in detecting wall thinning [15][16][17], cracks [18,19], corrosion under insulation [20], and leakage in buried pipes [21] and biofouling [22,23]. In particular, microwaves in the TM 01 mode with the axial surface current density and in TE 01 mode with the circumferential surface current density on the pipe wall showed high sensitivity to circumferential [18] and axial cracks (slits) [19] with the width about 1 mm, respectively.…”

Tube inner wall defect detection method based on rotary scanning micro laser distance sensor

“…In addition, Rao et al [11] applied a novel ultrasonic guided wave tomography method based on full waveform inversion for the inner wall of tube defect mapping and reconstructed the tube thickness map, but in practical inspection, the detection ability is greatly reduced due to the interference echo signal from the feature structure in the tube [12]. Shi et al [13] proposed a detection method for the inner wall damage of a small-diameter pipeline based on the TE01 mode microwave; the width of the pipeline defect is analyzed by the movement of the peak value of the echo signal of the microwave reflected wave, but the depth of the defection is not analyzed. The multi-arm caliper imaging logging tool [14] converts the change of casing wall into an electrical signal by contacting the measuring arm with the casing wall and the image of the tube inner surface can be restored on the ground.…”

Analysis via 3D FEM of the Passing Capacity of Pipeline Inspection Gauges in Bends with Different Curvatures

“…This can lead to fluctuations during operation, which, in turn, cause incomplete data collection and reduced detection accuracy [16]. In addition, the poor passing capacity may cause PIG blockages in the pipeline [17][18][19][20][21], leading to a pipeline outage and severe economic losses.…”