https://doi.org/10.1007/s11356-022-20859-x
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An important factor that characterises the operation of the RPB device is the rotating filling inside the housing. Therefore, it was necessary to simulate the flow on a dynamic mesh by defining the rotational elements of the model and giving them a specific rotational frequency. The velocity inlet boundary condition was used as the air inlet. The velocity inlet boundary condition was used as the air inlet. The application of this boundary condition was dictated by the method of measuring the air flow, which returned the value in m3/h, which was a value independent of the operating temperature of the apparatus. The domain exit condition was set to a pressure outlet with an operating pressure of 1 atmosphere. The geometry view with the gas inlet and outlet marked is shown in Fig. 6.
View of the geometry of the CFD model with the gas inlet and outlet marked
In this work, calculations of pressure drop for various conditions of single-phase (gas) flow through the RPB device with rotating packing were performed. For comparison, the parameters of the dry pressure drop test in the simulation were the same as the experimental conditions. Based on the obtained data, the numerical model was validated. The simulation performed calculations for two turbulence models to determine which one better and reflected the experimental results compared to the required calculation time.
Basic model parameters:
- Porosity: 0.922
- Interface size: 2800 m2 m-3
- Type of porous filling: isotropic metal foam
- Turbulence model: k-ε, RNG k-ε
- Rotational frequencies: 150–1500 rpm
- Volumetric gas flow rate: 20 m3 h-1, 40 m3 h-1, 60 m3 h-1
- No liquid flow
- The system is isothermal and the gas is incompressible
The obtained results for the presented basic model parameters were unsatisfactory; therefore, it was necessary to validate the model by introducing parameters describing the fill properties that determine momentum loss. The loss of momentum by an isotropic porous region can be described by parameters such as permeability (Kperm) and loss factor (Kloss).
In order to obtain the values of permeability and loss coefficient, additional experiments were carried out showing the dependence of the pressure losses through the filling fragment on the gas flow velocity. The obtained dependence is presented in Fig. 7. A stationary RPB device was used to perform the measurements, and two tightly insulated pieces of filling were placed inside the rotor (Fig. 8). The Kperrm and Kloss parameters calculated based on the relationships presented above were:
- Permeability (Kperm): 2.58 ∙ 10-8 m2;
- Loss factor (Kloss): 2744.11 m-1.
Gas pressure drop through stationary filling depending on the gas velocity
Experimental configuration for measuring the filling parameters for the CFD model
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