The plenum chamber of a heat setting machine is a key structure for distributing hot air to different air channels.Its outlet velocity uniformity directly determines the heating uniformity of textiles,significantly af...The plenum chamber of a heat setting machine is a key structure for distributing hot air to different air channels.Its outlet velocity uniformity directly determines the heating uniformity of textiles,significantly affecting the heat setting performance.In a traditional heat setting machine,the outlet airflow maldistribution of the plenum chamber still exists.In this study,a novel plenum chamber with an airfoil baffle was established to improve the uniformity of the velocity distribution at the outlet in a heat setting machine.The structural influence of the plenum chamber on the velocity distribution was investigated using a computational fluid dynamics program.It was found that a chamber with a smaller outlet partition thickness had a better outlet velocity uniformity.The structural optimization of the plenum chamber was conducted using the particle swarm optimization algorithm.The outlet partition thickness,the transverse distance and the longitudinal distance of the optimized plenum chamber were 20,686.2 and 274.6 mm,respectively.Experiments were carried out.The experimental and simulated results showed that the optimized plenum chamber with an airfoil baffle could improve the outlet velocity uniformity.The air outlet velocity uniformity index of the optimized plenum chamber with an airfoil baffle was 4.75%higher than that of the plenum chamber without an airfoil baffle and 5.98%higher than that of the conventional chamber with a square baffle in a commercial heat setting machine.展开更多
Polypropylene(PP) sheets are cast with various chill roll temperatures and rates, which are studied with differential scanning calorimetry, wide angel X-ray diffraction, scanning electronic microscopy and dielectric w...Polypropylene(PP) sheets are cast with various chill roll temperatures and rates, which are studied with differential scanning calorimetry, wide angel X-ray diffraction, scanning electronic microscopy and dielectric withstand voltage test system. The results show that increasing the chill roll temperature and cast rate can promote the increase of crystallinity and the growth of β-form. The PP sheets have asymmetric skin layer structures. The lower the chill roll temperature, the thicker the skin layer, the smaller the spherulite size. The electric breakdown strength(Eb) of PP sheets is mainly affected by the crystallinity but not the morphology. The PP sheets are further stretched to prepare bi-axially oriented PP(BOPP) films with various heat setting time. Our results indicate that the structure of PP sheets affects the properties of BOPP films. The as prepared BOPP films from the sheets cast at high chill roll temperature and rate have the highest crystallinity and Eb. Heat setting time has profound effect on the crystallinity and Eb, which increase first and then decrease with the heat setting time. It is expected that our study can provide guidance for optimizing process parameters.展开更多
In order to define the development direction of safe blasting technology in high-temperature coal seams in China, this paper presents a systematic, state-of-the-art review on safe blasting technology. Information such...In order to define the development direction of safe blasting technology in high-temperature coal seams in China, this paper presents a systematic, state-of-the-art review on safe blasting technology. Information such as high-temperature coal fire extinguishment and cooling, anti-high-temperature blasting supplies, heat insulation blasting setting, operation procedures for high-temperature blasting, and so on, are presented. Analysis shows that the development of effective technology for coal seam fire extinguishing and cooling, the manufacture of anti-high-temperature blasting supplies, especially priming materials, the development of heat insulation blasting setting, and the establishment of technical specifications suit large-scale blasting design and construction work at high-temperature coal seams, are the essential methods for safe blasting at high temperature coal seams.展开更多
Shape memory alloy metal rubber(SMAMR)is a novel intelligent elastic damping material which can realize the integration of structure and function.The investigations on the anisotropic mechanical characteristics which ...Shape memory alloy metal rubber(SMAMR)is a novel intelligent elastic damping material which can realize the integration of structure and function.The investigations on the anisotropic mechanical characteristics which depended on shaping craft and working temperature were conducted by quasi-static tests.Comparative experiments indicated that the heat setting temperature affect the elastic modulus non-monotonously but has little effect on the loss factor of SMAMR in both martensite and austenite phases.With the increase of the heat setting time,the elastic modulus of SMAMR monotonously decreases and the reduction of loss factor is unobvious.With the present shaping craft,SMAMR exhibits the anisotropy in moulding and non-moulding directions,which is affected by the heat setting process and working temperature.It was proved that the mechanical properties have approximately linear relationship with temperature during the phase transition process.Due to its temperature-dependent mechanical properties,SMAMR that experiences the heat setting procedure is expected to be used in active vibration control systems with varying temperature-dependent stiffness and damping coefficients to provide superior vibration control performance.展开更多
Building simulation is a powerful way to evaluate the performance of a building.The quality of simulation results however strongly depends on the accuracy of simulation input data.Especially for weather data files and...Building simulation is a powerful way to evaluate the performance of a building.The quality of simulation results however strongly depends on the accuracy of simulation input data.Especially for weather data files and occupant behaviour it is difficult to obtain accurate data.This paper evaluates the variability of building simulation results with regards to different weather data sets as well as different heating and cooling set points for a residential building in Victoria,Australia.Thermal comfort accord-ing to ASHRAE Standard 55,final energy consumption and peak cooling and heating loads are assessed.Simulations have been performed with Energy-Plus,and weather data for a multi-year approach have been generated with the software Meteonorm.The results show that different weather files for the same location as well as different conditioning set points can influence the results by approximately a factor of 2.展开更多
基金National Natural Science Foundation of China(No.62173307)the Key R&D Projects of Science and Technology Department of Zhejiang Province,China(Nos.2023C01158,2022C01065 and 2022C01188)the Fundamental Research Funds of Zhejiang Sci-Tech University,China(No.22242298-Y)。
文摘The plenum chamber of a heat setting machine is a key structure for distributing hot air to different air channels.Its outlet velocity uniformity directly determines the heating uniformity of textiles,significantly affecting the heat setting performance.In a traditional heat setting machine,the outlet airflow maldistribution of the plenum chamber still exists.In this study,a novel plenum chamber with an airfoil baffle was established to improve the uniformity of the velocity distribution at the outlet in a heat setting machine.The structural influence of the plenum chamber on the velocity distribution was investigated using a computational fluid dynamics program.It was found that a chamber with a smaller outlet partition thickness had a better outlet velocity uniformity.The structural optimization of the plenum chamber was conducted using the particle swarm optimization algorithm.The outlet partition thickness,the transverse distance and the longitudinal distance of the optimized plenum chamber were 20,686.2 and 274.6 mm,respectively.Experiments were carried out.The experimental and simulated results showed that the optimized plenum chamber with an airfoil baffle could improve the outlet velocity uniformity.The air outlet velocity uniformity index of the optimized plenum chamber with an airfoil baffle was 4.75%higher than that of the plenum chamber without an airfoil baffle and 5.98%higher than that of the conventional chamber with a square baffle in a commercial heat setting machine.
基金financially supported by the State Key Laboratory of Advanced Power Transmission Technology (No.GEIRI-SKL2020-009)。
文摘Polypropylene(PP) sheets are cast with various chill roll temperatures and rates, which are studied with differential scanning calorimetry, wide angel X-ray diffraction, scanning electronic microscopy and dielectric withstand voltage test system. The results show that increasing the chill roll temperature and cast rate can promote the increase of crystallinity and the growth of β-form. The PP sheets have asymmetric skin layer structures. The lower the chill roll temperature, the thicker the skin layer, the smaller the spherulite size. The electric breakdown strength(Eb) of PP sheets is mainly affected by the crystallinity but not the morphology. The PP sheets are further stretched to prepare bi-axially oriented PP(BOPP) films with various heat setting time. Our results indicate that the structure of PP sheets affects the properties of BOPP films. The as prepared BOPP films from the sheets cast at high chill roll temperature and rate have the highest crystallinity and Eb. Heat setting time has profound effect on the crystallinity and Eb, which increase first and then decrease with the heat setting time. It is expected that our study can provide guidance for optimizing process parameters.
文摘In order to define the development direction of safe blasting technology in high-temperature coal seams in China, this paper presents a systematic, state-of-the-art review on safe blasting technology. Information such as high-temperature coal fire extinguishment and cooling, anti-high-temperature blasting supplies, heat insulation blasting setting, operation procedures for high-temperature blasting, and so on, are presented. Analysis shows that the development of effective technology for coal seam fire extinguishing and cooling, the manufacture of anti-high-temperature blasting supplies, especially priming materials, the development of heat insulation blasting setting, and the establishment of technical specifications suit large-scale blasting design and construction work at high-temperature coal seams, are the essential methods for safe blasting at high temperature coal seams.
基金supported by the National Natural Science Foundation of China (Grant Nos. 51105022,51101008 and 51211130115)Fan Zhou Research Fund (Grant No. 201104021)
文摘Shape memory alloy metal rubber(SMAMR)is a novel intelligent elastic damping material which can realize the integration of structure and function.The investigations on the anisotropic mechanical characteristics which depended on shaping craft and working temperature were conducted by quasi-static tests.Comparative experiments indicated that the heat setting temperature affect the elastic modulus non-monotonously but has little effect on the loss factor of SMAMR in both martensite and austenite phases.With the increase of the heat setting time,the elastic modulus of SMAMR monotonously decreases and the reduction of loss factor is unobvious.With the present shaping craft,SMAMR exhibits the anisotropy in moulding and non-moulding directions,which is affected by the heat setting process and working temperature.It was proved that the mechanical properties have approximately linear relationship with temperature during the phase transition process.Due to its temperature-dependent mechanical properties,SMAMR that experiences the heat setting procedure is expected to be used in active vibration control systems with varying temperature-dependent stiffness and damping coefficients to provide superior vibration control performance.
文摘Building simulation is a powerful way to evaluate the performance of a building.The quality of simulation results however strongly depends on the accuracy of simulation input data.Especially for weather data files and occupant behaviour it is difficult to obtain accurate data.This paper evaluates the variability of building simulation results with regards to different weather data sets as well as different heating and cooling set points for a residential building in Victoria,Australia.Thermal comfort accord-ing to ASHRAE Standard 55,final energy consumption and peak cooling and heating loads are assessed.Simulations have been performed with Energy-Plus,and weather data for a multi-year approach have been generated with the software Meteonorm.The results show that different weather files for the same location as well as different conditioning set points can influence the results by approximately a factor of 2.
