Real-time Flow Analysis Research Articles

Development of Autonomous Recovery System for Pipeline of Naval Ships by Using a Multistage Control Algorithm

Pipeline systems in naval ships with special combat purposes (such as warships) are frequently exposed to the risk of damage. It is necessary to detect and isolate such unexpected damage quickly via an autonomous recovery system in the pipelines to ensure the ships survivability. This recovery system employs an autonomously controlled valve, which consists of a valve body, two pressure sensors, an actuator to open/close the valve, and a controller equipped with damage detection capability and a control algorithm. To enhance the reliability of the autonomous recovery system, this study first proposes a multistage control (MSC) algorithm that can comprehensively consider the various damage scenarios in a naval ship and then suggests the design procedure for the autonomous piping system based on support vector machine (SVM). To design the suggested algorithm, a simulation model for the one-dimensional real-time flow analysis is first established, and its results for possible damage scenarios are used as training data for the SVM with the valve operation information for recovery of the piping system and to minimize the damaged area. A performance comparison of the representative control algorithms for the autonomous piping system is conducted via flow simulations under three representative damage scenarios. Finally, a real-scale testbed of the firemain in a naval ship is designed and constructed, and the effectiveness of the algorithm is demonstrated through experiments.

진동수주형 파력발전장치의 챔버 및 터빈 내 유동해석을 위한 실시간 물리적 모델 구현에 관한 연구

This study was carried out to implement real-time physical model for the flow analysis in the oscillating chamber and the pneumatic turbine of the OWC(Oscillating Water Column)-type wave power generator. This device is a system that extracts energy by rotating the turbine by repeating the vertical motion of a water column in an air chamber by an incident wave. The turbine is operated by the pressure difference between the air chamber and the outside atmosphere. A digital twin model is required for efficient operation and maintenance of wave generator. It is a technology that can control the real model by predicting the phenomenon in real time after N seconds based on the physical model and the sensor data model. In this study, a real-time flow analysis physical model was implemented from the energy conservation equation to predict the air pressure in the chamber. In order to build a physical model, three-dimensional flow analysis data in the turbine were considered. To validate this analytical model, the air pressure in the chamber was compared to the experimental data and showed good quantitative agreement over the entire time.

Bio-inspired Flexible Lateral Line Sensor Based on P(VDF-TrFE)/BTO Nanofiber Mat for Hydrodynamic Perception.

Fish and some amphibians can perform a variety of behaviors in confined and harsh environments by employing an extraordinary mechanosensory organ, the lateral line system (LLS). Inspired by the form-function of the LLS, a hydrodynamic artificial velocity sensor (HAVS) was presented in this paper. The sensors featured a polarized poly (vinylidene fluoride-trifluoroethylene) [P(VDF-TrFE)]/barium titanate (BTO) electrospinning nanofiber mat as the sensing layer, a polyimide (PI) film with arrays of circular cavities as the substrate, and a poly(methyl methacrylate) (PMMA) pillar as the cilium. The P(VDF-TrFE)/BTO electrospinning nanofiber mat demonstrated enhanced crystallinity and piezoelectricity compared with the pure P(VDF-TrFE) nanofiber mat. A dipole source was employed to characterize the sensing performance of the fabricated HAVS. The HAVS achieved a velocity detection limit of 0.23 mm/s, superior to the conventional nanofiber mat-based flow sensor. In addition, directivity was feasible for the HAVS, which was in accordance with the simulation results. The proposed bio-inspired flexible lateral line sensor with hydrodynamic perception ability shows promising applications in underwater robotics for real-time flow analysis.

Blood Flow Pattern Analysis for Carotid Plaque Evaluation

Background and PurposePrevious studies suggested that turbulent flow is closely related to plaque vulnerability. Two-dimensional (2D) flow analysis is a novel modality that enables real-time blood flow analysis by picturing particle movement in the contrast medium. We evaluated flow patterns in the carotid plaque to investigate the correlation between blood flow and plaque vulnerability. Material and MethodsA total of 36 consecutive patients with cervical carotid artery stenosis were evaluated. The flow pattern of carotid artery stenosis was evaluated using 2D real-time flow analysis in the digital subtraction angiography (DSA). The flow pattern was classified into either turbulent or laminar flow as vectors. Plaque vulnerability was evaluated on MR plaque imaging. Univariate analysis was performed to assess the correlation between the flow pattern and plaque features. ResultsThe turbulent pattern was identified in 28 of 36 plaques (77.8%). Turbulence around plaques was significantly associated with Gadolinium enhancement (P = .0004). The maximum degree of stenosis (P = .0005) and concomitant ulceration (P = .02) were significantly associated with the turbulent pattern. There was no relationship between the turbulent pattern and clinical neurological symptoms. ConclusionsIn the present study, the majority of carotid plaques exhibited a turbulent flow pattern, which was significantly associated with Gadolinium enhancement on MR plaque imaging and morphologic factors. Thus, real-time flow analysis may clarify the pathophysiology of plaque instability and the formation of ulceration.

Preclinical feasibility of a technology framework for MRI-guided iliac angioplasty.

Interventional MRI has significant potential for image guidance of iliac angioplasty and related vascular procedures. A technology framework with in-room image display, control, communication and MRI-guided intervention techniques was designed and tested for its potential to provide safe, fast and efficient MRI-guided angioplasty of the iliac arteries. A 1.5-T MRI scanner was adapted for interactive imaging during endovascular procedures using new or modified interventional devices such as guidewires and catheters. A perfused vascular phantom was used for testing. Pre-, intra- and post-procedural visualization and measurement of vascular morphology and flow was implemented. A detailed analysis of X-ray fluoroscopic angiography workflow was conducted and applied. Two interventional radiologists and one physician in training performed 39 procedures. All procedures were timed and analyzed. MRI-guided iliac angioplasty procedures were successfully performed with progressive adaptation of techniques and workflow. The workflow, setup and protocol enabled a reduction in table time for a dedicated MRI-guided procedure to 6 min 33 s with a mean procedure time of 9 min 2 s, comparable to the mean procedure time of 8 min 42 s for the standard X-ray-guided procedure. MRI-guided iliac vascular interventions were found to be feasible and practical using this framework and optimized workflow. In particular, the real-time flow analysis was found to be helpful for pre- and post-interventional assessments. Design optimization of the catheters and in vivo experiments are required before clinical evaluation.

Implementation of Water Management System Based on MiddleBlock-Centered Monitoring

The evaluation standards of management efficiency for managing the water supply can be called the Revenue Water Ratio. The revenue water ratio is an important index that shows the standards on the cost of production as well as the ratio of quantities received through the rate income from the total amount of water supply produced from the water treatment plant. In general, the calculation of revenue water ratio is made on the basis of small blocks after the progression of blocking business, thus the management of water pipe network is also made on the basis of small block unit. However, the boundaries of adjacent blocks have many obscure points with many number of blocks, there are many difficulties of performing the work by the limited management personnel. Therefore in this paper, in order to improve the problems and limits of the previous block monitoring system based on inefficient small blocks, a block monitoring system based on real-time flow analysis centering on the middle block is proposed. In addition, by performing the dynamic pattern-based abnormal flow analysis considering the characteristics of each block and also by performing the real-time analysis on the rate of water supply between the classes, it will prove that the efficiency of management can be improved.