Qianqian Shao¹, Min Wang^2,*, Nuo Xu¹

CMES-Computer Modeling in Engineering & Sciences, Vol.139, No.2, pp. 1337-1356, 2024, DOI:10.32604/cmes.2023.044313

Abstract To investigate the influences of co-flow and counter-flow modes of reactant flow arrangement on a proton exchange membrane fuel cell (PEMFC) during start-up, unsteady physical and mathematical models fully coupling the flow, heat, and electrochemical reactions in a PEMFC are established. The continuity equation and momentum equation are solved by handling pressure-velocity coupling using the SIMPLE algorithm. The electrochemical reaction rates in the catalyst layers (CLs) of the cathode and anode are calculated using the Butler-Volmer equation. The multiphase mixture model describes the multiphase transport process of gas mixtures and liquid water in the fuel cell. After validation, the influences… More >

Shihong Zhang^*，Zhihua Wang

Frontiers in Heat and Mass Transfer, Vol.4, No.2, pp. 1-6, 2013, DOI:10.5098/hmt.v4.2.3005

Abstract This article discussed exhaust gas temperature and pollutant emissions characteristics of the combustion of rich natural gas-air mixtures in Pd metal based honeycomb monoliths burner during the period of start-up process. The burner needs to be ignited by gas phase combustion with the excessive air coefficient (a) at 1.3. The chemistry at work in the monoliths was then investigated using the stagnation point flow reactor or SPFR. The experimental results in catalytic monolith can be explained from SPFR. The exhaust gas temperature and pollutant emissions were measured by thermocouple K of diameter 0.5 and the analyser every 1 minute, respectively.… More >

B. Orr^a,* , R. Singh^a, A. Akbarzadeh^b , M. Mochizuki^c

Frontiers in Heat and Mass Transfer, Vol.13, pp. 1-7, 2019, DOI:10.5098/hmt.13.8

Abstract Heat pipes that operate in the medium temperature range (550-700 K) are very rarely used in industry despite the potential demand of use. There is no consensus about suitable working fluids in this temperature range as research on possible working fluids is limited. One proposed working fluid is naphthalene. In this paper, a number of tests have been undertaken on both an individual naphthalene heat pipe and a naphthalene heat pipe heat exchanger. Unlike room temperature working fluids, medium temperature working fluids are solid at ambient temperature therefore they have unusual transient start up behaviour. Testing has indicated that these… More >

Felix Schily^a,∗, Wolfgang Polifke^a

Frontiers in Heat and Mass Transfer, Vol.17, pp. 1-15, 2021, DOI:10.5098/hmt.17.16

Abstract A simple open-loop pulsating heat pipe model is proposed, which allows to analytically determine the start-up behavior by a linear stability analysis. Two distinct types of instability can occur in such a pulsating heat pipe: oscillatory and non-oscillatory. This paper demonstrates that for bubbles consisting of non-condensible gas, large temperature gradients along the wall are required to achieve start-up, whereas start-up is fairly easy to achieve when there is only a single working medium that forms bubbles from its vapor. The study also finds that surface tension as such only influences start-up indirectly, while contact angle hysteresis dampens out any… More >

Xuanyu Dong^1,*, Jingyao Yang²

FDMP-Fluid Dynamics & Materials Processing, Vol.19, No.1, pp. 175-185, 2023, DOI:10.32604/fdmp.2022.021345

Abstract A new numerical model for low-permeability reservoirs is developed. The model incorporates the nonlinear characteristics of oil-water two-phase flows while taking into account the initiation pressure gradient. Related numerical solutions are obtained using a finite difference method. The correctness of the method is demonstrated using a two-dimensional inhomogeneous low permeability example. Then, the differences in the cumulative oil and water production are investigated for different starting water saturations. It is shown that when the initial water saturation grows, the water content of the block continues to rise and the cumulative oil production gradually decreases. More >

S. Green^∗

Computer Systems Science and Engineering, Vol.35, No.4, pp. 257-269, 2020, DOI:10.32604/csse.2020.35.257

Abstract The digital revolution impacts modern workplaces through constant advances in technology. This study uses a digital start-up project experience to demonstrate how a Digital Government Transformation can be beneficial. The increase of administrative requirements, compliance, and capability readiness has prompted the development of the Digital start–up project known as the CARM Tool (Compliance, Assurance and Risk Management). CARM introduces a low risk low cost and high productivity solution, which can directly and immediately benefit stakeholders in a large complex government enterprise. It aims to elevate staff performance, customer service and provide qualification between financial statements, asset management and alignment with… More >