Open Access

ARTICLE

A Mathematical Model of Heat Transfer in Problems of Pipeline Plugging Agent Freezing Induced by Liquid Nitrogen

Yafei Li, Yanjun Liu^*

Southwest Petroleum University, Chengdu, 610500, China

* Corresponding Author: Yanjun Liu. Email:

(This article belongs to the Special Issue: EFD and Heat Transfer IV)

Fluid Dynamics & Materials Processing 2022, 18(3), 775-788. https://doi.org/10.32604/fdmp.2022.019810

Received 16 October 2021; Accepted 28 December 2021; Issue published 22 February 2022

Abstract

A mathematical model for one-dimensional heat transfer in pipelines undergoing freezing induced by liquid nitrogen is elaborated. The basic premise of this technology is that the content within a pipeline is frozen to form a plug or two plugs at a position upstream and downstream from a location where work a modification or a repair must be executed. Based on the variable separation method, the present model aims to solve the related coupled heat conduction and moving-boundary phase change problem. An experiment with a 219 mm long pipe, where water was taken as the plugging agent, is presented to demonstrate the relevance and reliability of the proposed model (results show that the error is within 18%). Thereafter, the model is applied to predict the cooling and freezing process of pipelines with different inner diameters at different liquid nitrogen refrigeration temperatures when water is used as the plugging agent.

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