Asphalt mixture pavement reheating is one of the important steps in hot in-place recycling(HIR).To improve the heating speed of asphalt pavement in HIR,based on the numerical analysis model of asphalt mixture heating ...Asphalt mixture pavement reheating is one of the important steps in hot in-place recycling(HIR).To improve the heating speed of asphalt pavement in HIR,based on the numerical analysis model of asphalt mixture heating process,a new multi-layer low-temperature heating method(MLHM)was proposed.Considering input heat flux,the thermal capacity and thermal resistance of asphalt mixture,the heat transfer model was established based on energy conservation law.By heating the asphalt mixture in layers,it changes the situation that the heat energy can only be input from the upper surface of the asphalt mixture pavement.Through the simulation of the heating method of asphalt mixture in the existing technology,the result shows that the existing heating methods lead to serious aging or charring of the asphalt mixture.By MLHM,the upper and the bottom of the asphalt mixture are heated at the same time,and the heating temperature is lower than other heat methods,which not only reduces the heating thickness and increases the heating area of the asphalt mixture pavement,but also improves the heating speed,saves the energy resource and ensures the heating quality.Especially,by MLHM,the heating uniformity is better and speed is faster.展开更多
A solar still system is designed and built to utilize solar energy in the Gulf States region to produce fresh water from brackish and sea water. This experimental work has been conducted with and without a cooling tub...A solar still system is designed and built to utilize solar energy in the Gulf States region to produce fresh water from brackish and sea water. This experimental work has been conducted with and without a cooling tube. The results showed that the daily production rate of the simple solar still without a cooling tube is slightly higher than that with a cooling tube. This could be due to the fact that the cooling tube has a smaller effective condensation surface area than the glass cover of the simple still. The cooling tube also reduces the solar energy that reaches the water in the still. It might also be due to the fact that the use of a cooling tube has the effect of reducing the average temperature in the solar still cavity. This resulted in reducing the evaporation rate and consequently reduced the production rate.展开更多
基金Project(2017JM5077)supported by the Natural Science Basic Research Plan in Shaanxi Province,ChinaProjects(300102259109,300102259306)supported by the Fundamental Research Funds for the Central Universities,China。
文摘Asphalt mixture pavement reheating is one of the important steps in hot in-place recycling(HIR).To improve the heating speed of asphalt pavement in HIR,based on the numerical analysis model of asphalt mixture heating process,a new multi-layer low-temperature heating method(MLHM)was proposed.Considering input heat flux,the thermal capacity and thermal resistance of asphalt mixture,the heat transfer model was established based on energy conservation law.By heating the asphalt mixture in layers,it changes the situation that the heat energy can only be input from the upper surface of the asphalt mixture pavement.Through the simulation of the heating method of asphalt mixture in the existing technology,the result shows that the existing heating methods lead to serious aging or charring of the asphalt mixture.By MLHM,the upper and the bottom of the asphalt mixture are heated at the same time,and the heating temperature is lower than other heat methods,which not only reduces the heating thickness and increases the heating area of the asphalt mixture pavement,but also improves the heating speed,saves the energy resource and ensures the heating quality.Especially,by MLHM,the heating uniformity is better and speed is faster.
文摘A solar still system is designed and built to utilize solar energy in the Gulf States region to produce fresh water from brackish and sea water. This experimental work has been conducted with and without a cooling tube. The results showed that the daily production rate of the simple solar still without a cooling tube is slightly higher than that with a cooling tube. This could be due to the fact that the cooling tube has a smaller effective condensation surface area than the glass cover of the simple still. The cooling tube also reduces the solar energy that reaches the water in the still. It might also be due to the fact that the use of a cooling tube has the effect of reducing the average temperature in the solar still cavity. This resulted in reducing the evaporation rate and consequently reduced the production rate.
