Study on similarity criteria for heat exchange system of underground coal fires

In order to carry out coalfield fire model experiment under the condition of multi-field coupling,similarity transform for the mathematical model of heat exchange system was performed using the similarity theory.On this basis,a research approach was presented that take the temperature field of the equilibrium state to obtain the general characteristics of temperature distribution in coalfield fire areas by analyzing the characteristic of underground coal fires evolution process.Ten similarity criteria,including thermal stress similarity,thermal storage similarity and heat emission similarity were selected as the similarity criteria of underground coal fires.The similarity relationship between the model and the prototype was established.Taking a certain fire area for example,an experimental design for coal fires heat exchange system was developed to analyze the mapping relationship between underground high-temperature region and thermal surface anomalies after mining subsidence cracks have developed.