Huayuan ZHOU

Huayuan ZHOU

HVACer, CFDer, PhD candidate in Civil Engineering

Sitemap

A list of all the posts and pages found on the site. For you robots out there is an XML version available for digesting as well.

Pages

Posts

projects

The dependency and flux of the ozone and fine particulate pollution over the ocean

Sub-project for social development of Shanghai Science and Technology Innovation Action Plan, Advisor: Prof. Ke Zhong, 2024

The formation process of sea-land breeze and the dispersion trajectory and accumulation effect of pollutants are studied under different velocities of OBW with the same sea-land temperature difference by employing computational fluid dynamics (CFD).

Study on the time-delay effect of haze pollution in indoor environment

General project of National Natural Science Foundation of China, Advisor: Prof. Yanming Kang, 2024

As a frequently occurred phenomenon in the past decade, especially in recent years, hazy weather or haze pollution has become an emergent environmental issue which is highly concerned in many scientific fields in China. Haze pollution not only raises particle concentration indoors during haze episodes by indoor-outdoor air exchange, but also worsens indoor air quality after the episodes due to its time-delay effects. When haze weather passed, the fine particles, which deposited on the walls of ventilation systems and formed dendritic structures, particularly in ducts, would resuspend into the incoming air by flow flushing and other impactions, and then enter into indoor environment. This phenomenon causes a time-dependent delay of indoor haze pollution， i.e.，a relatively long-time pollution duration （with a relatively high concentration） indoors related to the haze episode. However, investigations and analyses are still lack on this problem and similar/corresponding topics.

Study on the coupling transportations of aerosol in hazy environment within the canopy of urban micro-scale environment

General project of National Natural Science Foundation of China, Advisor: Prof. Yanming Kang, 2024

The impact of particulate matter (PM) on indoor air quality (IAQ) has become an important issue in China, whereas the standard for the filtration of PM in building ventilation has not been promulgated up to now. Due to the impacts of particle size distribution (PSD) on the particle removal efficiency of the air filters, and also due to the various characteristics of local PSD across China, it is necessary to analyze the selection of PSD when evaluating particle removal efficiency for practical applications. Although the efficiency of PM (ePMX) for various particle size ranges, proposed in the latest EN ISO 16890 standard, is used to evaluate the actual effect of air filters for building ventilation on the improvement of IAQ, it is inappropriate to be adopted for the cases in China. In the present study, fine particle proportion (PM2.5/PM10) is employed and ambient aerosol distributions across China are analyzed. The measured PSDs at 35 cities are fitted to bimodal distribution. And then the ePMX and class reporting values (CRVs) of three representative filters are calculated. The results indicate that being affected by the characteristics of PSD, the ePMX and CRV differences of the same air filter between different PSD regions can be up to about 20% and 15%, respectively. Therefore, the China PSD regions are divided into five regions and the standardized PSD is determined for each region of the mainland.

Structure Optimization of Fan Filter Unit (FFU)

4/2018 – 3/2019, Advisor: Prof. Ke Zhong, 2024

By modeling the Fan Filter Unit (FFU), simulating the airflow in the FFU and analyzing the results, the internal air ducts can be optimized to reduce resistance and noise.

publications

Indoor Formaldehyde and Benzene Series in Shanghai Residences and Their Associations with Building Characteristics and Lifestyle Behaviors

Published in Environment Science, 2018

From March 2013 to December 2014，we on-site inspected indoor concentrations of formaldehyde and a benzene series in 454 children's bedrooms that were decorated earlier than one year before our inspection. Large differences existed in the formaldehyde and benzene-series concentrations among individual bedrooms. Bedrooms that were inspected in winter had significantly higher concentration of formaldehyde than bedrooms that were inspected in other seasons (P < 0. 001) ，but the benzene-series concentration had no significant seasonal difference. Among bedrooms that were inspected in spring，those using different materials as wall coverings had significant differences in concentrations of the benzene series. Among bedrooms that were inspected in summer，those using different materials as floor coverings had significant differences in concentrations of the benzene series (P < 0. 01) . Among bedrooms that were inspected in autumn，those with > 5 household bonsais had significantly higher concentrations of formaldehyde than other bedrooms did. Among bedrooms that were inspected in winter，those with frequent use of air humidifiers and those in which pets were kept had significantly higher concentrations of the benzene series than other bedrooms did (P < 0. 05) . These results indicate that， after a long time since decoration，the types of household wall and floor covering materials still have certain relationships with indoor benzene-series levels and，compared to decoration materials，household ventilation perhaps has greater effect on indoor formaldehyde levels. The indoor benzene-series level perhaps has associations with indoor humidity level and the keeping of pets in households. Household bonsaies may have limited effect on indoor formaldehyde and benzene-series levels in residences that were decorated a long time ago.

Recommended citation: Q. Jiang, P. Liu, X. Wang, R. Lu, W. Liu, H. Zhou, Y. Gong, Y. Zhou, C. Huang. Indoor Formaldehyde and Benzene Series in Shanghai Ｒesidences and Their Associations with Building Characteristics and Lifestyle Behaviors. Environment Science. 39 (2018) 585–591. https://doi.org/10.13227/j.hjkx.201703144. http://KennyZhou2022.github.io/files/01-Indoor-Formaldehyde-and-Benzene-Series-in-Shanghai-Residences-and-Their-Associations-with-Building-Characteristics-and-Lifestyle-Behaviors.pdf

Relationship between indoor temperature, relative humidity, ventilation and formaldehyde, benzene-series concentrations in children’s bedrooms

Published in Jounal of Environment and Health, 2018

Objective To understand the relationship between indoor temperature，relative humidity，ventilation and formaldehyde， benzene-series concentrations in children’s bedrooms. Methods During March 2013-December 2014，indoor concentrations of formaldehyde and benzene-series were monitored on site in 454 children’s bedrooms decorated for more than one year，the relationship between them and indoor temperature，relative humidity，ventilation was analyzed. Results The mean concentrations of formaldehyde and benzene-series in these bedrooms were 21.5 μg/m3 and 33.5 μg/m3，respectively in whole period，27.7 μg/m3 and 42.4 μg/m3 respectively in winter，which were significantly higher compared with other seasons (P<0.01). The daily-averaged concentration of formaldehyde had significantly negative correlations with daily-averaged temperature in the bedrooms in autumn and winter，as well as relative humidity in summer and winter (P<0.05). No significant correlations were found between daily-averaged concentration of benzene-series and indoor daily-averaged temperature，relative humidity (P> 0.05). Indoor ventilation in winter was obviously lower compared with other seasons. Monthly ventilation rates had significantly negative correlation with indoor concentrations of formaldehyde in bedrooms (r=-0.651，P<0.05). Conclusion Indoor ventilation significantly effects concentrations of formaldehyde and benzene-series in the children’s bedrooms decorated for more than one year much stronger than indoor temperature and relative humidity do.

Recommended citation: P. Liu, H. Zhou, X. Wang, R. Lu, W. Liu, Q. Jiang, Y. Gong, Y. Zhou, C. Huang. Relationship between indoor temperature, relative humidity, ventilation and formaldehyde, benzene-series concentrations in children's bedrooms. Jounal of Environment and Health. 35 (2018) 991–994. https://doi.org/10.16241/j.cnki.1001-5914.2018.11.014. http://KennyZhou2022.github.io/files/02-Relationship-between-indoor-temperature-relative-humidity-ventilation-and-formaldehyde-benzene-series-concentrations-in-childrens-bedrooms.pdf

Studies on the most unfavorable distance between the upstream building and the windward building in street canyons in urban area

Published in China Environmental Science, 2019

Numerical simulations were conducted to investigate the influence of the distance between the upstream building and the downstream building in street canyons (D) on characteristics of air flow and distributions of gaseous pollutants in the canyons. The simulation results showed that the wind velocities in the windward regions in the canyons did not change with the change of D. However, the wind velocities in the leeward and central regions decreased first and then increased with the increase of D, and the minimum value occurred when D = 90m. Correspondingly, the peak concentration of the pollutant in the canyons appeared at the same D, which indicated the most unfavorable value of D existed. In urban planning, it should be avoided as far as possible. When D was more than 90m, the larger the D was, the lower the pollutant concentration would be. When D was less than 90m, the smaller the D was, the lower the concentration would be, which could be benefit for both land-saving and traffic pollution reduction.

Recommended citation: H. Zhou, Y. Kang, F. Yang, G. Liu, K. Zhong. Studies on the most unfavorable distance between the upstream building and the windward building in street canyons in urban area.China Environmental Science. 39 (2019) 4125–4132. https://doi.org/10.19674/j.cnki.issn1000-6923.2019.0483. http://KennyZhou2022.github.io/files/03-Studies-on-the-most-unfavorable-distance-between-the-upstream-building-and-the-windward-building-in-street-canyons-in-urban-area.pdf

Influences of offshore background wind on the formation of sea-land breeze and the characteristics of pollutant diffusion

Published in Environmental Science and Pollution Research, 2021

The formation of sea-land breeze (SLB) is primarily affected by background wind and temperature difference between the sea and nearby land. Because the intensity of sea breeze is significantly stronger than that of land breeze, land breeze may result in more accumulated pollutants under the condition of offshore background wind (OBW) than under the condition of no OBW in coastal areas. The formation process of sea-land breeze and the dispersion trajectory and accumulation effect of pollutants are studied under different velocities of OBW with the same sea-land temperature difference by employing computational fluid dynamics (CFD). The results reveal that the depth and the duration of sea breeze decrease with the increase of the velocity of OBW. The most unfavorable velocity of OBW (0.2 m s-1) exists when the concentration affected by OBW is higher than that by no OBW in coastal areas. The pollutants close to the ground will be blown to the inland by sea breeze when the velocity of OBW is less than 1.0 m s-1. When the velocity of OBW is larger than 2.0 m s-1, the pollutants will not occur on the inland due to the influence of OBW.

Recommended citation: J. Xu, H. Jia, H. Zhou, Y. Kang, K. Zhong, Influences of offshore background wind on the formation of sea-land breeze and the characteristics of pollutant diffusion, Environ Sci Pollut Res. 28 (2021) 68318–68329. https://doi.org/10.1007/s11356-021-15339-7. http://KennyZhou2022.github.io/files/04-Influences-of-offshore-background-wind-on-the-formation-of-sea-land-breeze-and-the-characteristics-of-pollutant-diffusion.pdf

Regional standardized particle size distributions for developing a Chinese filter testing standard used in building ventilation

Published in Journal of Building Engineering, 2021

The impact of particulate matter (PM) on indoor air quality (IAQ) has become an important issue in China, whereas the standard for the filtration of PM in building ventilation has not been promulgated up to now. Due to the impacts of particle size distribution (PSD) on the particle removal efficiency of the air filters, and also due to the various characteristics of local PSD across China, it is necessary to analyze the selection of PSD when evaluating particle removal efficiency for practical applications. Although the efficiency of PM (ePMX) for various particle size ranges, proposed in the latest EN ISO 16890 standard, is used to evaluate the actual effect of air filters for building ventilation on the improvement of IAQ, it is inappropriate to be adopted for the cases in China. In the present study, fine particle proportion (PM2.5/PM10) is employed and ambient aerosol distributions across China are analyzed. The measured PSDs at 35 cities are fitted to bimodal distribution. And then the ePMX and class reporting values (CRVs) of three representative filters are calculated. The results indicate that being affected by the characteristics of PSD, the ePMX and CRV differences of the same air filter between different PSD regions can be up to about 20% and 15%, respectively. Therefore, the China PSD regions are divided into five regions and the standardized PSD is determined for each region of the mainland.

Recommended citation: H. Zhou, Y. Sun, K. Zhong, Y. Wang, J. Cai, Y. Kang, Regional standardized particle size distributions for developing a Chinese filter testing standard used in building ventilation, Journal of Building Engineering. 44 (2021) 102972. https://doi.org/10.1016/j.jobe.2021.102972. http://KennyZhou2022.github.io/files/05-Regional-standardized-particle-size distributions-for-developing-a-Chinese-filter-testing-standard-used-in-building-ventilation.pdf

Analysis of the effects of dynamic mesh update method on simulating indoor airflow induced by moving objects

Published in Building and Environment, 2022

Local interference flow induced by the movement of human bodies or objects indoors can directly affect breathing air quality. However, very few studies have been carried out on the flow induced by moving objects due to high experimental costs. As an alternative, computational fluid dynamic (CFD) method has been employed in predicting the flow induced by moving objects indoors. During the numerical computations, the mesh needs to be updated continuously for the moving objects behave as part of the boundary. Although the dynamic mesh update (DMU) methods have been used in the CFD method, the performances of these DMU methods vary widely, and it is still lack of analysis on the selection of the DMU methods. In this study, the DMU methods provided by ANSYS FLUENT are used for comparing the numerical performances between computational and experimental results. Five aspects of numerical performance, accuracy, mesh quality, mesh generation complexity, continuity, and computational efficiency, are discussed integrally. The results show the dynamic layering (DL) method is preferred for the case of linear movement due to the high computational efficiency and accuracy though it is difficult and time-consuming in mesh generation. Spring-based smoothing & remeshing (SS&R) method can be used when the complicated-shaped or nonlinearly moving objects are part of the boundary. Both computational efficiency and accuracy of overset mesh (OM) method are low when the moving objects are clinging to the boundary, so this method is not recommended for simulating the flow fields.

Recommended citation: H. Zhou, K. Zhong, H. Jia, Y. Kang, Analysis of the effects of dynamic mesh update method on simulating indoor airflow induced by moving objects, Building and Environment. 212 (2022) 108782. https://doi.org/10.1016/j.buildenv.2022.108782. http://KennyZhou2022.github.io/files/06-Analysis-of-the-effects-of-dynamic-mesh-update-method-on-simulating-indoor-airflow-induced-by-moving-objects.pdf

talks