In a distribution network of low-pressure gas pipelines, the situation of gas leak can be further aggravated when groundwater enters the pipeline through leaks and eventually blocks the gas flow. This will have critical implications on the gas supply to the customers. This is termed as 'water ingress', which typically happens only in low-pressure distribution networks, and not in high-pressure transmission networks. In order to find the location of water ingress, distributed temperature sensing (DTS) system has been used experimentally. The results show significant temperature change immediately after the onset of water ingress, and with data post-processing based on temporal difference, location information of the leak can be obtained. With a selected time window of interest, the inclination of gas pipeline is also indicated by the differenced temperature profiles. The DTS system is still capable of identifying the position, even if the location of water ingress is changed.
In underground low-pressure gas distribution pipelines, ground water enters the pipeline through cracks. This is known as the water ingress problem, and it occurs predominantly in the monsoon season when the water table is high. This issue is currently detected based on complaints from the users. In order to arrive at an efficient and reliable processing technique, experimental results of pressure and flow on an existing low-pressure gas pipeline are reported in the present paper. Several experiments for leak location, severity of the leak, water ingression with various volumes of water followed by removal of water are conducted. Healthy network loading data collected over a 24 hr period is used to verify the robustness of the derived parameters for water ingression detection. The present technique can detect leaks easily with a leak valve opening of 30 o . Robust detection of water ingression with more than 10% of pipe volume is possible.
Natural convection flow in a differentially heated square enclosure filled with porous matrix with a solid adiabatic thin fin attached at the hot left wall is studied numerically. The Brinkman-Forchheimer-extended Darcy model is used to solve the momentum equations, in the porous medium. The numerical investigation is done through streamlines, isotherms, and heat transfer rates. A parametric study is carried out using the following parameters: Darcy number (Da) from 10 −4 to 10 −2 , dimensionless thin fin lengths (L p ) 0.3, 0.5, and 0.7, dimensionless positions (S p ) 0.25, 0.5, and 0.75 with Prandtl numbers (Pr) 0.7 and 100 for Ra = 10 6 . For Da = 10 −3 and Pr = 0.7, it is observed that there is a counter clock-wise secondary flow formation around the tip of the fin for S p = 0.5 for all lengths of L p . Moreover when Da = 10 −2 the secondary circulation behavior has been observed for S p = 0.25 and 0.75 and there is another circulation between the top wall and the fin that is separated from the primary circulation. However, these secondary circulations features are not observed for Pr = 100. It is also found that the average Nusselt number decreases as the length of the fin increases for all locations. However, the rate of decrease of average Nusselt number becomes slower as the location of fin moves from the bottom wall to the top wall. The overall heat transfer rate can be controlled with a suitable selection of the fin location and length.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.