CFD analysis of Part-Load operation of an Open-Circuit Induced-Draft cooling tower

Castiglione, T.; Nicoletti, Francesco; Ferraro, Vittorio; Sangineto, C.M.

doi:10.1016/j.applthermaleng.2023.120636

Cited by 6 publications

(3 citation statements)

References 32 publications

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“…Since the fluid flow is highly turbulent with relatively high velocity, the CFD solver solves the Reynolds Number formula for the transport equation. Equation obtains the Mass-Conservation Equation where S p is the source term and represents the transfer from the discrete particle phase to the gas phase. ∂ ∂ x i ( ρ u i ) = S normalp Equation solves the Reynolds-Average Navier–Stokes (RANS) Equation to simulate the momentum transport of the synthetic ammonia gas phase . The Boussinesq model is used to approximate the Reynolds stress, ρu i ′ u j ′ , which can be used in various two-equation turbulence models and has the advantage of low computational cost.…”

Section: Numerical Modeling Methodsmentioning

confidence: 99%

“…However, the model they proposed was still two-dimensional and had not been applied to study the impact at varying production loads. Castiglione et al 19 used computational fluid dynamics to model the induced ventilation evaporation tower and found that when 60% load was operated, the process parameters of the tower were very close to the design parameters, but the water evaporated was reduced by half and the power required by the fan was significantly reduced. Laubscher et al 20 describes a CFD modeling methodology used to evaluate the thermal performance of the water wall evaporator, platen, and final stage superheaters of a subcritical pulverized coal-fired boiler at full and reduced boiler loads.…”

Section: Introductionmentioning

confidence: 99%

“…Equation 9 solves the Reynolds-Average Navier−Stokes (RANS) Equation to simulate the momentum transport of the synthetic ammonia gas phase. 19 The Boussinesq model is used to approximate the Reynolds stress, ρu i ′u j ′, which can be used in various two-equation turbulence models and has the advantage of low computational cost. The Reynolds stress tensor τ eff in the Boussinesq hypothesis can be written as eq 10.…”

mentioning

confidence: 99%

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How to Achieve Flexible Green Ammonia Production: Insights via Three-Dimensional Computational Fluid Dynamics Simulation

Zhang,

Li,

Zhou

et al. 2024

Ind. Eng. Chem. Res.

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The green ammonia synthesis process involves producing ammonia using hydrogen obtained from electrolyzing water with renewable energy sources, thereby contributing to carbon emission reduction and promoting sustainable development. However, in large-scale commercial operations, there exists a contradiction between the volatility of renewable energy and the stability required in chemical production processes: the fluctuation of the power supply and feedstocks constantly brings new changes to the heat and mass transfer of the fluid in the reactor, which will pose a severe challenge to the flexibility of reactor operation. In this study, we utilized a combination of reaction kinetics and computational fluid dynamics (CFD) to conduct three-dimensional modeling of the green ammonia reactor with validation against industrial data. The proposed novel approach facilitated the prediction of spatial flow field distribution within the reactor and assessment of varying load impacts on green ammonia yield and production index. The results indicate minimal deviation in processing parameters from baseline operating conditions under varying loads, yet a notable reduction in green ammonia yield occurs with decreased production loads, nearly reducing by 50%. Through the sensitivity analysis, the optimal operation scheme under different production loads is proposed. For example, at 30% load, the optimal operating pressure and hydrogen/nitrogen ratio are 14 MPa and 3.1, which are quite different from the baseline operating conditions. However, such process flexibility comes at the expense of catalyst and energy utilization, decreasing exergy efficiency by approximately 30% and potentially leading to operational anomalies such as gas dead spaces, low-temperature zones, and backflow, underscoring the trade-offs inherent in enhancing process flexibility. Nonetheless, the application potential of the green ammonia flexible synthesis process remains promising. Our proposed three-dimensional reactor simulation offers theoretical underpinnings for ensuring stability and optimal operation regulation in green ammonia production.

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