Advanced Materials Research Vols. 243-249

Abstract: The aim of this paper is to study the control effects of pollutants with different ventilation methods in industrial buildings. Comparative researches are conducted between the push-pull ventilation system and displacement ventilation system. Formaldehyde (HCHO) is selected as the main pollutant in the industrial buildings in this paper. The computational fluid dynamics (CFD) is used to analysis the space distribution of pollutant concentrations with the pollution sources at different locations. Through comparative study，the pollutants distribution with the same supply air volume and pollutants diffusion intensity are evaluated from the following two aspects. Firstly, when the height of the pollutant source is 1.2 m in the industrial building, the average concentration of the contaminant at the space section with push-pull ventilation system is relatively higher than that with displacement ventilation system. Secondly, the average concentration with push-pull ventilation system is 0.00058 kmol/m³ while displacement ventilation system is 0.00097 kmol/m³ when the height of the pollutant source is 0.6 m. And when it is 0.3 m, they are 0.00016 kmol/m³ and 0.0017 kmol/m³ respectively. Thus, the concentration of the contaminant in displacement ventilation is higher than the push-pull ventilation’s with the location of the pollution source continuously declining in the height direction.

Abstract: The relationship between formaldehyde emission and time was researched and a mathematical model was developed which describes the variation of formaldehyde with time in the airtight chamber. It was found that high quality composite floor was in line with 0-order kinetic equation and low quality composite floor was in line with 1-order kinetic equation. Besides, the effect of activated carbon adsorption on formaldehyde was studied and the result showed that activated carbon had poor adsorption on formaldehyde for weak van der waals force.

Abstract: In order to investigate on diversities of existing condition of coalbed methane in same stratum and various moisture content states, raw coking and meager coal have been adopted and a series of experimental equipments for fixed volume adsorption have also been designed. Further dealing with analyses of adsorption velocities, capacities or mechanisms, six different moisture contents of 1# coking and 2# meager cylinder block coal samples have been chosen separately to engage in the typical experiments of coalbed methane adsorption. From the adsorptive experiments, the existing condition of coalbed methane in the real stratum has been illustrated. The results showed that: a) at the same initial gas injection pressure, the adsorption velocities are decreased with the increased of moistures. Gas pressure declines are 22 and 16 times of moisture content 0% than the saturation moistures separately. b) The simulation results of coalbed methane adsorption capacities followed by moistures are linear of 1# and nonlinear of 2# separately. c) At the different moistures, time effect characteristics of adsorption capacity is logarithmic and would not be getting to equilibrium state until undergoing 12 hours or even more. Also simulative constant values are disaffinity in different coal degrees. d) By ways of the analyses in basis of experimental results on adsorptive mechanism between gas and water, the adsorbability of coalbed methane affected by water is related to macro fractures distribution on the surface of coal samples.

Abstract: This document established a three-dimensional laminar mathematical and physical model which describes heat transfer, mass transfer coupling process in wet thermal recovery unit for air-conditioning systerms, based on Computational Fluid Dynamics (CFD) simulations. In addition, the research discussed the distributions of pressure, temperature, concentration and other parameters in the air channels. The heat transfer performance was analyzed by enthalpy efficiency. The results showed that the structural parameters of wet thermal recovery unit for air-conditioning systerm played important influence in the heat transfer performance and flow drag performance. The research set a foundation for the optimal design of wet thermal recovery unit for air-conditioning systerm.

Abstract: Establish a nonlinear membership function of slope stability taking the case of six different sliding blocks on a typical slope and do a second class fuzzy comprehensive evaluation on the determinate membership. Comparing the result of stability evaluated with former result determined by extension classified method, it shows that it is basically conforming to evaluate slope stability using membership function which is established according to the changing rules of impact factors of slope such as quality of rock, massiveness of rock mass and dip angle of rock. This method can be referential in a qualified sense for the forecasting and preventing of landslide disasters.

Abstract: Through carried out computer simulation analysis on air-to-air energy recovery equipment，the analysis research mainly aims at pressure drop characteristics among the factors which influence the core of the heat exchanger，the results show that：as the plate spacing, plate width, plate height, as well as changes in a secondary air inlet velocity core，all of them will have different effects on the air-to-air energy recovery unit of the resistance loss, which is useful to air-to-air energy recovery unit to optimize the design.

Abstract: A natural and environment friendly refrigerant propylene (R1270) is proposed as a substitute of R22 in the residential air conditioner. The experiments on the cooling performance of the air conditioner with R1270 and R22 were respectively conducted on an existing enthalpy potential bench, during the degree of superheating keep constant and refrigerant charge directly on the conditioner, also the effect on system performance in the condensing temperature was tested, it is founded that the cooling capacity of R1270 air conditioner was 96% that of R22 air conditioner while the COP of the former increased, and the refrigerant charge amount of R1270 was 56.8 % lower than R22.

Abstract: Recreational guild hall usually has the characteristic of the special architectural form, complex architectural adornment and high requirement of indoor temperature/humidity, airflow distribution, noise and lighting. Air conditioning system design was optimized based on architecture environment requirement of recreational guild hall. The method was applied on the air conditioning system design of Nanjing Longjing recreational guild hall and the effect is satisfactory.

Abstract: This article takes underground powerhouse as engineering objects, adopting manual and automatic monitoring way to measure the inlet air temperature and the relative humidity of the 7 cross-sections underground traffic tunnel, and the temperature inside the cave wall in 3 working conditions. Furthermore, this article analyzes the results and expounds the causes for fog and condensation inside the tunnel. Finally, it proposes some effective measures to solve the problems, which can be applied to the similar air conditioning system design of the underground buildings.

Abstract: The indoor thermal comfort labels for the heating system with on-off valve regulation has been proposed by Fanger’s PMV/PPD. Experiments were conducted to investigate the thermal comfort of heating system with on-off valve regulation in point to the living habits and clothing situation of residents in North China. The computational fluid dynamic (CFD) software AIRPAK was adopted in the evaluations. The indoor airflow distribution, PMV of different transient heating process were simulated. The indoor human comfort and changes were analyzed and compared. It was found that the indoor thermal comfort is satisfactory for the heating system with on-off valve regulation.