The laboratory LAMTI has worked for several years on the study and the optimization of the thermal performances of passive solar walls like solar Trombe wall. These components of the buildings envelope have very compl...The laboratory LAMTI has worked for several years on the study and the optimization of the thermal performances of passive solar walls like solar Trombe wall. These components of the buildings envelope have very complex behaviour because they are the seat of various coupled heat transfers modes and are subjected to the random variations of the meteorological parameters. Using the finite difference method （FDM） and starting from experimental results recorded during several years, a simulation model was developed and validated concerning the ＂composite＂ Trombe wall. In order to make this work more accessible to the community of the heat engineers, it appears interesting to build a simulation model which can be integrated into the library of elements of the TRNSYS software. A ＂Type＂ was thus carried out and the results obtained compared with those of the FDM model. In this work we compare the obtained results with these two numerical ways. The assumptions and the results of simulations are also confronted with those of an existing module in TRNSYS （Type 36） established for the ＂classical＂ Trombe wall. The study shows that the models that we developed are very precise and that certain assumptions must be used with a lot of precautions. The advantages of the composite Trombe solar wall compared to the Classical Trombe wall are highlighted for cold and/or cloudy climates.展开更多
Considering that the particular geometric shape of a quasi-rectangular shield,the grout flowing law and its motion process are more complicated than those of a conventional circular shield.To interpret the grouting me...Considering that the particular geometric shape of a quasi-rectangular shield,the grout flowing law and its motion process are more complicated than those of a conventional circular shield.To interpret the grouting mechanical ehaviour in the special-shape shield tail void,the filling and diffusion mechanism of synchronous grouting was analysed.The grout flowing is separated into two independent motion processes,which contains a circumferential filling and a longitudinal diffusion.The theoretical model of the grout pressure spatial distribution was derived based on the principle of fluid mechanics.Then,the pressure distributions in the two directions were obtained using a case study and compared with the field measured data to verify the validation of the model.Although the overall spatial pattern of grout pressure distribution on the tunnel profile show a change trend dominated by the self-weight effect mostly,its local fluctuation characteristics is very abnormal relative to that of a circular shield tunnel.Moreover,the important factors in the model were analysed,including the grout material parameters,the grouting construction parameters,and some geometry parameters.The results show that the pressure loss along this way is positively correlated with the grout flow velocity and is sensitive to the shear yield stress of the grout.The pressure loss along the circumferential direction is the most sensitive to the thickness of the ring cake,and the value range suitable for the model should be 0.02-0.03 m.The pressure loss along the longitudinal diffusion direction is the most sensitive to the size of the tail void.The research results can provide a theoretical basis for the control of special-shape shield construction.展开更多
文摘The laboratory LAMTI has worked for several years on the study and the optimization of the thermal performances of passive solar walls like solar Trombe wall. These components of the buildings envelope have very complex behaviour because they are the seat of various coupled heat transfers modes and are subjected to the random variations of the meteorological parameters. Using the finite difference method （FDM） and starting from experimental results recorded during several years, a simulation model was developed and validated concerning the ＂composite＂ Trombe wall. In order to make this work more accessible to the community of the heat engineers, it appears interesting to build a simulation model which can be integrated into the library of elements of the TRNSYS software. A ＂Type＂ was thus carried out and the results obtained compared with those of the FDM model. In this work we compare the obtained results with these two numerical ways. The assumptions and the results of simulations are also confronted with those of an existing module in TRNSYS （Type 36） established for the ＂classical＂ Trombe wall. The study shows that the models that we developed are very precise and that certain assumptions must be used with a lot of precautions. The advantages of the composite Trombe solar wall compared to the Classical Trombe wall are highlighted for cold and/or cloudy climates.
基金sponsored by the Shanghai Rising-Star Program of China(Grant No.18QB1403800)supported by the Fundamental Research Funds for the Central Universities(Grant No.21D111320).
文摘Considering that the particular geometric shape of a quasi-rectangular shield,the grout flowing law and its motion process are more complicated than those of a conventional circular shield.To interpret the grouting mechanical ehaviour in the special-shape shield tail void,the filling and diffusion mechanism of synchronous grouting was analysed.The grout flowing is separated into two independent motion processes,which contains a circumferential filling and a longitudinal diffusion.The theoretical model of the grout pressure spatial distribution was derived based on the principle of fluid mechanics.Then,the pressure distributions in the two directions were obtained using a case study and compared with the field measured data to verify the validation of the model.Although the overall spatial pattern of grout pressure distribution on the tunnel profile show a change trend dominated by the self-weight effect mostly,its local fluctuation characteristics is very abnormal relative to that of a circular shield tunnel.Moreover,the important factors in the model were analysed,including the grout material parameters,the grouting construction parameters,and some geometry parameters.The results show that the pressure loss along this way is positively correlated with the grout flow velocity and is sensitive to the shear yield stress of the grout.The pressure loss along the circumferential direction is the most sensitive to the thickness of the ring cake,and the value range suitable for the model should be 0.02-0.03 m.The pressure loss along the longitudinal diffusion direction is the most sensitive to the size of the tail void.The research results can provide a theoretical basis for the control of special-shape shield construction.
