Study On The Method Of Calculating The Thickness And Average Temperature Of Freezing Wall Under Different Pipe Layouts

At present,in the problem of freezing wall temperature field by artificial freezing method,how to reasonably calculate the thickness and average temperature of freezing wall is a problem in the research of freezing temperature field,especially the freezing of multi-row pipe and multi-circle pipe,which lacks high precision.The calculation formula of the reliability.Aiming at this subject,through the combination of analytical analysis and numerical calculation,the development rules of freezing front and average temperature under various piping methods are studied,and the thickness of the freezing wall and the average temperature applicable to different piping methods are proposed.Firstly,based on the similarity theory,using ANSYS finite element software,the single-pipe,single-row pipe,single-ring pipe,double-row pipe,double-ring pipe,multi-row pipe and multi-ring pipe freezing temperature field similar models were established,and similar numerical calculations were performed.The development process of the freezing temperature field from transient to steady state is simulated,and the law of the freezing wall temperature field developing with time is obtained.Secondly,the freezing temperature field of the multi-row pipe and the multi-loop pipe are studied separately by strips,and the relationship between the influencing factors,the mutual influence between the frozen pipe,the cross-over time,and the freezing time of the strips are analyzed.The freezing front and average temperature of the characteristic surface and the development law of the average temperature of the entire freezing area are obtained.Finally,based on the problems of single-pipe freezing and round pipe heat conduction,through comparison,the calculation formulas for the thickness of the frozen wall and the average temperature of the single-row pipe and the single-circle pipe are obtained.Studying the mutual influence of different rows or circles of frozen pipe,we obtained the condition that the effect of frozen pipe on non-adjacent frozen strips can be ignored,so as to extend the conclusion of single row pipe and single ring pipe to double row pipe and double ring pipe.The fitting formula of the average temperature of the middle strip of the double-row pipe and the double-coil pipe is fitted.The effect of multi-row pipe and multi-turn pipe freeze pipe on non-adjacent frozen strips was further studied,and a large number of numerical calculations were used to summarize the calculation method of the average temperature of the frozen strips between two adjacent rows or between two turns.The conclusions of the pipe and double-coil pipe are extended to multi-row pipe and multi-coil pipe,and finally the calculation method of the thickness of the freezing wall and the average temperature of the freezing temperature field of any row or circle number is finally obtained.The research results of this paper provide a basis for designing the frozen wall more reliably and conveniently in practical engineering.The paper has 208 pictures,16 tables,and 99 references.