Optimal Design And Experiment Research Of The Environment Control System In A Mine Rescue Cabin

Environment control system is a important technology in investigation of emergency refuge and life support in underground mine, which is significant part in refuge cabin and refuge chamber. Design of non-source machine with functions of both refrigeration purification is a key point in improving system applicability and stability. In this paper control of temperature and humidity inside the cabin as well as gas purification and positive pressure control are investigated by theoretical calculation, numerical simulation and experiment, meanwhile the distribution of airflow field inside the cabin is simulated and the environment inside the cabin is evaluated on account of comfortable degree of human body. As for the capsule environment control system, a comprehensive design optimization system combining theory with experiments is firstly put forward in this thesis, which fulfills the comprehensive design and evaluation process from theoretical calculation to single experiment and then to multi-parameters experiment verification.The thesis has the following major contents:(1) Classification and calculation of temperature, humidity, and air pollution inside the cabin.Thermal and moisture load of the cabin as well as pollution air load in the disaster environment are analyzed and calculated. Thermal and moisture load is divided into human body metabolic load, chemical heat load and structure heat load. According to the dynamic variation rule of thermal and humidity load, design criterion of “minimum design cooling load” and “steady maximum heat load with longtime ” is proposed while system stability and design safety margin are improved by means of proper distribution of subjective body heat load and objective environment heat load. Meanwhile metabolisation velocity of CO and CO2 is calculated, it is found that the electrochemical sensor would be influenced by NH3 and H2 S. The calculation of temperature and humidity as well as pollution air load provides boundary condition in the design of environment control system inside the cabin.(2) Experimental investigation and optimization design of purification system.The carbon monoxide purification in the refuge cabin is in the field of low concentration purification in room temperature, which means the selection and performance test in the refuge cabin of low temperature catalyst is extremely valuable. Based on the experimental study on the performances of catalyst such as R-90, MXY-II and nano-gold, the purification rate of each catalyst under different inlet concentration is calculated, and the stability of catalytic under low concentration is compared and analyzed. As for the carbon dioxide purification, the purification rate of agent under hanging and paving conditions is analyzed by experiment testing the soda-lime absorption performance. On that basis, a new placing method which combines paving with hanging is provided, improving using efficiency under the design requirement of rapid removal rate.Maintaining positive pressure is a significant condition to ensure the refuge cabin not affected by the external toxic and harmful gas, but the pressure release valves applied in refuge chamber field all have the disadvantage of poor air tightness, which increases the storage demand of compressed air in the cabin. To solve the air tightness problem of pressure relief valves, an automatic fluid seal micro differential pressure relief valve with high sealing performance is designed and the theoretical pressure relief ability is calculated. According to the air tightness experiment, the air leakage rate in the chamber is calculated and the design criterion of the cabin positive pressure air compensation is presented. A positive pressure aeration system for mine-used refuge cabin is firstly established and a theoretical guide is offered for the refuge chamber positive pressure control system design and positive pressure compensating control operation.(3) The design and optimization of open-loop CO2 refrigeration system.The refrigeration loss of open-loop CO2 refrigeration system is an important part in design and optimization of refrigeration system, including:(1) Leakage heat loss produced by heat exchange between cylinders and storage environment;(2) Efficiency loss produced by residual gas which could not be sufficiently used inside the cylinder. In this paper calculation model of open-loop CO2 refrigeration system is established while the variation trend of first and second part of loss mentioned above with critical state under environment temperature of CO2. On the basis two types of refrigeration loss are calculated, indicating that under higher storage environment temperature, refrigeration loss becomes higher belong which the second part is the major part.The distribution of flow resistance in the open-loop system will directly influence the refrigeration performance as well as system stability. Single stage throttling system is optimized to double stage throttling system according to the research of copper pipe length and frost length in the heat exchanger. On the basis the influence of pipe diameter, mass flow rate as well as ambient temperature and relative humidity to refrigeration system is investigated by distributed parameter model. The mechanism of ice block in open-loop CO2 refrigeration system is firstly theoretical analyzed in this paper. Meanwhile package line with adaptability to environment is investigated which provides theoretical guidance for adjustment and operation of the system, in order to ensure the stability and efficiency of the system.(4) Analysis of comfort degree inside the refuge cabin.The simulation model established for the cabin is an important method to analyze the flow field in the cabin. The simulation model of a certain type of 12-persons refuge cabin is established, and the air flow, temperature and humidity distribution as well as air concentration distribution are analyzed, and the distribution uniformity index ADPI, thermal comfort index PMV-PPD and air pollution index PAV-PDA are calculated. On this basis, the grey correlation analysis method based on entropy weight is used to calculate the weight of each evaluation index, and the method for evaluating comprehensive comfort degree of the air environment in the refuge chamber is obtained.(5) Experiment investigation of environment control system in the refuge cabin.The refrigeration and purification machine is designed and produced, and then 48-hour stability verification experiment and a 119-hour experiment with person are proceeded. Through the analysis of the phenomenon of " upstream transfer of flow resistance”, the operation and adjustment method of the integrated machine is further optimized, which provides the experimental basis for stable running with non-frost and without ice block of the system. In the comprehensive experiment with person, the environmental temperature and humidity, air concentration and positive pressure in the cabin are controlled in the design range, which successfully passes the product certification of the inspection center and the safety standard center of the nation. The refrigeration and purification machine and the environmental control method are used in the construction of many refuge chambers and refuge cabins underground.