FlameRoomWithTubeBundle L2_Static
Created Tuesday 18 June 2013
A 0d-flame room model with stationary mass and energy balance regarding heat exchange with neighbouring furnace models and convective and/or radiative heat transfer to tube bundles, carrier tubes and boiler casing walls.
1. Purpose of Model
This model is well suited to model the superheater and convective heating areas of a boiler. In combination with Hopper_L2, Burner_L2_Static and FlameRoom_L2_Static models a 1-dimensional boiler model could be achieved which is discretised in flow direction. Radiative and/or convective heat transfer between linked furnace models, boiler casing walls, carrier tubes and/or tube banks can be calculated using replaceable models.
2. Level of Detail, Physical Effects Considered and Physical Insight
2.1 Level of Detail
Referring to Brunnemann et al. [1], this model refers to the level of detail L2.
2.2 Physical Effects Considered
- this model uses TIL-Media
- stationary conservation of energy (neglecting kinetic energy terms)
- stationary conservation of mass
- combustion of unburnt fuel from lower burner or flame room models is considered
- outlet composition is calculated according to the elemental composition of the burnt fuel in the replaceable model CoalReactionZone
- enthalpy of formation is calculated for an
- the lower heating value of the burnt fuel is given or calculated according to the "Verbandsformel"
- calculation of radiative and/or convective heat transfer to tube bundles
- calculation of radiative or convective heat transfer to boiler casing walls
- calculation of convective heat transfer to carrier tubes
- constant pressure (until now no pressure losses are implemented)
2.3 Level of Insight
Heat Transfer
The following listed heat transfer models are the recommended ones. Of course other (e.g. generic ones: Generic HT) heat transfer models could be chosen.
top (radiation to neighbored furnace volumes)
- Basics:ControlVolumes:Fundamentals:HeatTransport:Generic HT:Adiabat L2: no heat transfer to downstream volume
wall (radiation or convection to boiler casing walls) :
- Basics:ControlVolumes:Fundamentals:HeatTransport:Gas HT:Radiation:Radiation gas2Wall L2: calculation of radiant heat transfer between furnace model and boiler casing walls with constant emissivity and absorbance values
- Basics:ControlVolumes:Fundamentals:HeatTransport:Gas HT:Radiation:Radiation gas2Wall advanced L2: calculation of radiant heat transfer between furnace model and boiler casing walls with constant or calculated emissivity and absorbance values (temperature dependent calculation of gas and particle emissivities)
- Basics:ControlVolumes:Fundamentals:HeatTransport:Gas HT:Convection:Convection flatWall L2: calculation of convective heat transfer to boiler casing walls
tube bundle (radiation and/or convection to tube bundle)
- Basics:ControlVolumes:Fundamentals:HeatTransport:Gas HT:Convection:Convection tubeBank L2: calculation of convective heat transfer between furnace model and tube bank
- Basics:ControlVolumes:Fundamentals:HeatTransport:Gas HT:Convection:ConvectionAndRadiation tubeBank L2: calculation of radiant and convective heat transfer between furnace model and tube banks
- Basics:ControlVolumes:Fundamentals:HeatTransport:Gas HT:Convection:Convection finnedTubes L2: calculation of convective heat transfer between furnace model and finned tube bank
carrier tubes (convection carrier tubes) :
- Basics:ControlVolumes:Fundamentals:HeatTransport:Gas HT:Convection:Convection carrierTubes laminar L2: calculation of convective heat transfer to carrier tubes
Pressure Loss
No pressure losses are considered.
The following replaceable models are used to model the combustion of fuel inside the different furnace volume models. The model for the chemical conversion of fuel can be chosen with the replaceable model ChemicalReactions. The models BurningTime and ParticleMigration are used to calculate the amount of fuel burned inside the current furnace volume. If the preset burning time is lower than the time span for the fuel particles needed to travel though the current furnace volume, the complete amount of fuel is burned inside this component. If the burning timer is higher than the particle migration time, unburnt fuel is entering the following downstream furnace model.
Chemical Reaction
- CoalReactionZone: calculates the outlet composition for combustion of the used fuel and its elemental composition.
Burning Time
- ConstantBurningTime: setting a fixed value for the time needed to burn the whole amount of fuel entering the combustion volume.
Particle Migration
- FixedMigrationSpeed: setting a fixed value for the time span needed for particles to travel through the combustion volume.
- MeanMigrationSpeed: calculates a mean value for the time span needed for particles to travel through the combustion volume.
3. Limits of Validity
- flow in design direction is considered only
4. Interfaces
4.1 Physical Connectors
Basics:Interfaces:FuelSlagFlueGas inlet inlet
Basics:Interfaces:FuelSlagFlueGas outlet outlet
Basics:Interfaces:HeatPort a heat_top
Basics:Interfaces:HeatPort a heat_bottom
Basics:Interfaces:HeatPort a heat_wall
Basics:Interfaces:HeatPort a heat_CarrierTubes
Basics:Interfaces:HeatPort a heat_TubeBundle
4.2 Medium Models
- Gas Medium Model at the inlet and outlet ports and additional ones inside the volume needed for the calculation of combustion processes.
5. Nomenclature
6. Governing Equations
6.1 System Description and General model approach
This model is used to build up furnace models with 1-dimensional discretisation and is used together with other models of the furnace package.
This model uses stationary mass and energy balances. The amount of burned fuel takes the particle migration time and the burning time from the replaceable model BurningTime into account. The lower heating value of the fuel can either be set in the parameter dialog or is calculated from the fuel's elementary analysis according to the "Verbandsformel" from [?]. Based on the elemental composition of the used fuel and a generalised ideal fuel combustion, the formation enthalpy is calculated to be considered in the energy balance.
All chemical reactions are calculated inside the replaceable model CoalReactionZone which determines the resulting flue gas mixture according to a combustion calculation and fixed parameters for the produced amount of CO and NOx, as well as the fraction of ash turned into slag. The slag moves through the furnace models in reverse direction (downwards). The slag outlet temperature is given by a parameter.
The component exchanges heat flows with up- and downstream models (via the heat ports heat_top and heat_bottom) as well as the surrounding walls (heat_wall) which are calculated with replaceable models for heat transfer correlations. If radiative heat transfer correlations are used inside a 1-dimensional discretised (sequential model arrangement) furnace, radiative heat flows are exchanged between the directly connected models (via heat ports top and bottom) and the surrounding walls (heat port wall). The calculation is performed with view factors which are calculated inside the heat transfer correlations. The following sketch shows the modelling principle for radiative heat transfer between the sequential arranged volumes and the calculation formula for the view factor. The amount of emitted radiation is calculated for a three dimensional volume, but the radiative heat flow between the models is assumed to be exchanged between two flat surfaces with the size of the furnace cross sectional area.
No backflow inside this model is considered. For correct calculation of backflows please use FlameRoomWithTubeBundle_L2_Dynamic with dynamic mass balance.
6.2 General Model Equations
The equation system of this component equals the one from FlameRoomWithTubeBundle_L2_Dynamic except the dynamic mass and energy balance of the flue gas. The mass balance of this Burner_L2 is not affected by the thermal expansion thus the dynamic expression is missing.
The energy balance is carried out stationary too.
The rest of the equation system equals FlameRoomWithTubeBundle_L2_Dynamic.
Summary
A summary record is available which bundles important component values.
7. Remarks for Usage
8. Validation
The adiabatic outlet temperature of this model has been validated with Ebsilon calculations at identical boundary conditions.
The image below shows the flue gas temperatures over the furnace height. As can be seen there is a good compliance with the design values.
9. References
[1] Johannes Brunnemann and Friedrich Gottelt, Kai Wellner, Ala Renz, André Thüring, Volker Röder, Christoph Hasenbein, Christian Schulze, Gerhard Schmitz, Jörg Eiden: "Status of ClaRaCCS: Modelling and Simulation of Coal-Fired Power Plants with CO2 capture", 9th Modelica Conference, Munich, Germany, 2012
10. Authorship and Copyright Statement for original (initial) Contribution
Author:
DYNCAP/DYNSTART development team, Copyright 2011 - 2022.
Remarks:
This component was developed during DYNCAP/DYNSTART projects.
Acknowledgements:
ClaRa originated from the collaborative research projects DYNCAP and DYNSTART. Both research projects were supported by the German Federal Ministry for Economic Affairs and Energy (FKZ 03ET2009 and FKZ 03ET7060).
CLA:
The author(s) have agreed to ClaRa CLA, version 1.0. See https://claralib.com/pdf/CLA.pdf
By agreeing to ClaRa CLA, version 1.0 the author has granted the ClaRa development team a permanent right to use and modify his initial contribution as well as to publish it or its modified versions under the 3-clause BSD License.
11. Version History
- 2013 - v 0.1 - initial implementation - L. Nielsen, A. Thüring, TLK-Thermo GmbH
- 08.01.2019 -v 1.4.0 - introduced parameter tubeOrientation, models are parametrisable in a more flexible way
- 26.03.2019 - chattering countermeasures applied (noEvents)
Backlinks: ClaRa:Components:Furnace:Burner:Burner L2 Static ClaRa:Components:Furnace:FlameRoom:FlameRoomAdditionalAir L2 Static ClaRa:Components:Furnace:FlameRoom:FlameRoom L2 Static