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Search Results (18)
  • Open Access


    High-Density Block Transformation to Increase Natural Ventilation Based on CFD Simulation

    Siqi Liu1,2,3, Guanqi Huang3,4,*

    FDMP-Fluid Dynamics & Materials Processing, Vol.17, No.1, pp. 141-157, 2021, DOI:10.32604/fdmp.2021.011990

    Abstract Many countries in the world have experienced extremely rapid urbanization during recent decades. The rapid development of densely populated areas has produced many urban environmental problems. This research explores the relationship between urban morphology and ventilation conditions. Through 3D modeling and Computational Fluid Dynamics (CFD) simulation, we focus on the large scale ventilation of an extended area with several buildings. As a testbed, in particular, the core part of Kwun Tong industrial park in Hong Kong is examined, and in order to validate the approach, 10 measurement points are used to get experimental values to be used for comparison (such… More >

  • Open Access


    Research on Optimal Matching of Heating Ventilation Air Conditioning System Based on Energy Saving Requirements

    Dongsheng Xu*

    Energy Engineering, Vol.117, No.3, pp. 143-152, 2020, DOI:10.32604/EE.2020.010335

    Abstract With the continuous development of society and the progress of science and technology, the living standards of the people also constantly improve, people pay more and more attention to the pursuit of material life, and the living space of everyday life and office space requirements are also rising, the air conditioning has become the essential in people’s daily life a kind of electrical equipment. The traditional optimal matching methods of heating, ventilation, air conditioning (HVAC) system have common problems such as long matching time, low matching accuracy and many matching times. The application of the best matching method of HAVC… More >

  • Open Access


    Dimensionless Study on Secretion Clearance of a Pressure Controlled Mechanical Ventilation System with Double Lungs

    Dongkai Shen1,2,+, Qian Zhang1, Yixuan Wang1,*, Huiqing Ge3,*, Zujin Luo4,+

    CMES-Computer Modeling in Engineering & Sciences, Vol.114, No.2, pp. 117-139, 2018, DOI:10.3970/cmes.2018.114.117

    Abstract A pressure controlled mechanical ventilator with an automatic secretion clearance function can improve secretion clearance safely and efficiently. Studies on secretion clearance by pressure controlled systems show that these are suited for clinical applications. However, these studies are based on a single lung electric model and neglect the coupling between the two lungs. The research methods applied are too complex for the analysis of a multi-parameter system. In order to understand the functioning of the human respiratory system, this paper develops a dimensionless mathematical model of double-lung mechanical ventilation system with a secretion clearance function. An experiment is designed to… More >

  • Open Access


    Computational techniques applied to design ventilation system for the preservation of the tombs of the valley of Kings, Luxor

    Essam E Khalil1

    The International Conference on Computational & Experimental Engineering and Sciences, Vol.15, No.2, pp. 47-56, 2010, DOI:10.3970/icces.2010.015.047

    Abstract The cultural heritage left by the Egyptian Pharaohs in the tombs of the Valley of the Kings represents some of the key elements of the Egyptian cultural and tourism wealth and standing monuments demonstrating the wealth and technology of the pharaohs. These tombs were prepared to bury the Kings' mummies and artifacts for eternal life. Many of the wall paintings identifying the various ancient rituals and life style are in good conditions as the tombs were only recently opened to the public and resulted, in many instances, to dramatic deterioration of the wall paintings due in part to excessive humidity.… More >

  • Open Access


    Tissue Strains Induced in Airways due to Mechanical Ventilation

    Ramana M. Pidaparti∗,†, Kittisak Koombua∗,‡

    Molecular & Cellular Biomechanics, Vol.8, No.2, pp. 149-168, 2011, DOI:10.3970/mcb.2011.008.149

    Abstract Better understanding of the stress/strain environment in airway tissues is very important in order to avoid lung injuries for patients undergoing mechanical ventilation for treatment of respiratory problems. Airway tissue strains responsible for stressing the lung's fiber network and rupturing the lung due to compliant airways are very difficult to measure experimentally. A computational model that incorporates the heterogeneity of the airways was developed to study the effects of airway tissue material properties on strain distributions within each layer of the airway wall. The geometry and boundary conditions of the tissue strain analysis were obtained from the organ-level analysis model.… More >

  • Open Access


    Biomechanical Aspects of Compliant Airways due to Mechanical Ventilation

    Kittisak Koombua*, Ramana M. Pidaparti∗,†,‡, P. Worth Longest∗,‡, Kevin R. Ward‡,§

    Molecular & Cellular Biomechanics, Vol.6, No.4, pp. 203-216, 2009, DOI:10.3970/mcb.2009.006.203

    Abstract Without proper knowledge of mechanical ventilation effects, physicians can aggravate an existing lung injury. A better understanding of the interaction between airflow and airway tissue during mechanical ventilation will be helpful to physicians so that they can provide appropriate ventilator parameters for intubated patients. In this study, a computational model incorporating the interactions between airflow and airway walls was developed to investigate the effects of airway tissue flexibility on airway pressure and stress. Two flow rates, 30 and 60 l/min, from mechanical ventilation were considered. The transient waveform was active inhalation with a constant flow rate and passive exhalation. Results… More >

  • Open Access


    A Correct Smoothed Particle Method to Model Structure-Ice Interaction

    Yang Liu1,*, Yue Qiao2, Tiange Li3

    CMES-Computer Modeling in Engineering & Sciences, Vol.120, No.1, pp. 177-201, 2019, DOI:10.32604/cmes.2019.06338

    Abstract This paper studies the effect of ice resistance on the icebreaking capacity and speed of an icebreaking vessel. We combine an improved Correct Smoothed Particle Method (CSPM) with a material low-speed collision fracture model to numerically simulate the continuous icebreaking and rolling process of crushed. Using this model, we investigate the icebreaking resistance and immersion resistance during the icebreaking process, taking into account the fluid (water) as the elastic boundary support and the fluid-solid coupling interaction. We compare the icebreaking resistance and broken ice fracture shapes obtained by the numerical calculation with the theoretical analytical results, and thus validate the… More >

  • Open Access


    Numerical Simulation and Ventilation Efficiency of Bicycle Helmets

    T.Z. Desta1, G. De Bruyne1, J.-M. Aerts1, M. Baelmans2, D. Berckmans1

    CMES-Computer Modeling in Engineering & Sciences, Vol.31, No.2, pp. 61-70, 2008, DOI:10.3970/cmes.2008.031.061

    Abstract This paper demonstrates the use of the concept of the local mean age of air (LMAA) to quantify ventilation effectiveness under bicycle rider's safety helmets. The specific objective is to study the effect of helmet openings on the resulting ventilation effectiveness. To quantify ventilation effectiveness using the concept of LMAA, dynamic tracer gas data are necessary. The data were generated using a Computational Fluid Dynamics (CFD) model. Two bicycle helmet designs were used and compared with respect to ventilation performance. The result showed that the helmet with more openings had better performance especially at the back of the head. The… More >

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