With the increasing process of urbanization in China, the phenomenon of the urban heat island becomes a serious problem due to the growing total number of buildings and human activities [
1]. Computational Fluid Dynamics (CFD) simulation can accurately simulate heat transfer and diffusion in a block [
2]; thus, providing the theoretical basis and reference for layout design and planning. Standard CFD simulation requires establishment of a detailed geometric model of the simulation area in large-scale simulations, which is not only complicated for modeling and pre-processing, but also has a long running time, a large amount of calculation, and a corresponding increase in simulation cost [
3]. The porous media model can use key parameters to reflect the overall characteristics of the region, simplify the model, and save the amount of calculation [
4,
5]. Therefore, based on the similarity between building blocks and porous media, a new method for simplifying building groups into porous media has emerged. In 1997, Antohe [
6] developed a porous turbulence model to study the flow of porous urban canopy, indicating that the porous media model has certain practical value in simulating large-scale urban areas. Hang [
7] regarded the city as a porous media, and the air in the city as an incompressible fluid passing through the porous media. By dividing the whole mixed region into porous urban areas and fluid areas, it is found that this method can significantly reduce the workload of modeling, meshing, and calculation in simulation. Gu Zhaolin et al. [
8] used the porous method and experiments to analyze the real urban area and found that the simulation results were in perfect agreement with the wind tunnel experimental results and verified the validity of the numerical model with the wind tunnel experimental results. Wang et al. [
9] compared and analyzed the three simulation results of the actual model, the roughness height model, and the mixed model of porous media modeling in some areas of the building clusters, and found that the porous media model is more effective and accurate than the roughness height model, and requires much less calculation. Li et al. [
10] validated the porous media simulation method and micro-scale CFD simulations for a relatively regular arrangement of settlements with a horizontal length of about 1 km in Xi’an, and the results showed that the wind velocity distribution and temperature distribution trends of both were in excellent agreement. Ming et al. [
11] established a concentric city structure and obtained the temperature and flow fields over the city using porous media simulations, and analyzed the effects of anthropogenic heat, ambient wind velocity, and porosity in the central region on urban turbulence and heat transfer. It is found that the three-dimensional turbulent porous media model is suitable for estimating the UHI effect. These studies demonstrate the practical value of applying the porous media model to urban building clusters and provide a reference and theoretical basis for this study.
In recent years, researchers have found that anthropogenic heat affects the urban thermal environment at different time and space levels [
12], which is one of the main driving forces that exacerbate global warming [
13,
14,
15,
16]. Especially in the city center area with high building density, the heat dissipation capacity is not ideal due to poor ventilation, and the impact of anthropogenic heat removal on the urban heat island effect cannot be ignored [
17,
18]. Anthropogenic heat emissions are mainly in the form of industrial heat emissions, traffic heat emissions, and household heat emissions into the atmospheric thermal environment [
19,
20]. The research on a large amount of urban anthropogenic heat by Du et al. [
21] showed that anthropogenic heat played an obvious role in aggravating the urban heat island effect. Xie Min et al. [
22] found that anthropogenic heat emissions have apparent regional characteristics, and the anthropogenic heat emissions in areas with a high degree of urbanization are significantly higher than those in other areas. Additionally, anthropogenic heat emissions vary with season and time [
23]. Takane et al. [
24] explored the impact of the feedback relationship between urban warming and air-conditioning use on atmospheric temperature in future urban climates and found that anthropogenic heat emissions from air-conditioning use would lead to a linear increase in the rate of temperature change. Ohashi et al. [
25] found that the waste heat from air conditioners in Osaka City in summer may cause the air temperature to increase by 0.36~0.72 °C. Tong Hua [
26] explored the effect of anthropogenic heat on the increase in urban temperature by estimating the intensity of anthropogenic heat emissions in Beijing, and evaluated the effect of reducing anthropogenic heat emissions on mitigating urban heat islands. Jiang Weimei [
27] found that the anthropogenic heat sources in Nanjing and Hangzhou could increase the heat island intensity by 1~3 °C. However, the research on anthropogenic heat mostly focuses on the statistical analysis of different anthropogenic heat source intensity in cities in different regions, as well as the analysis of the impact of anthropogenic heat on the thermal environment on the urban and even global scale [
28,
29,
30]. There is still a lack of research on the use of numerical simulation from the perspective of small and medium scales.
The simulation of predicted airflow around buildings has an essential impact on the outdoor microthermal environment, and the considerable simulation costs are one of the bottlenecks limiting the development of microclimates. There are significant difficulties in using ordinary computers to quickly implement thermal environment calculations in urban spaces, while porous media simulations can provide significant savings in computational costs and computational effort. Research on porous media for urban microthermal environments is still preliminary, and scholars are currently experimenting mainly on ideal building blocks and using wind tunnel experiments for verification. In this paper, an actual block is selected, and measured data are used to verify the applicability of the porous media model in the study of microthermal environments in the actual block. The effect of porosity and anthropogenic heat emissions on the microthermal environment is also explored, considering the inescapable role of anthropogenic heat emissions on the microthermal environment. The modeling results could be used to guide development of scientific urban development plans to mitigate the UHI effect.