ESP-r: network air/liquid flow modelling
Current capabilities
ESP-r capabilities for modelling bulk flows of air and/or liquids are as follows:
- steady flow of an incompressible fluid within a network
of connected pressure points when subjected to successive sets of boundary
conditions
- network may comprise sub-networks, each relating
to a different fluid type and equivalenced to a different building/ HVAC domain
- well adapted for building energy analysis but limited in relation to indoor
comfort and air quality (for which CFD may be a better option)
- includes a range of flow component models:
- power law volume & mass flow, quadratic law volume & mass flow
- constant volume & mass flow (adjustable via control)
- common orifice, air flow opening, air flow crack,
- general flow conduit, converging and diverging conduit
- door (bi-directional)
- general flow inducer, general & polynomial flow corrector,
- laminar pipe,
- link to CFD domain
- includes a range of controls
- on/off, proportional (with hysteresis), PID, range-based
- controls can be combined in parallel and/or in sequence
The aim of these definitions is to quickly and efficiently represent
builk air flow between rooms which are assumed to be well mixed. It can
support studies of natural ventilation and approximate user as well
as mechanical control interactions.
Primary routines
- mfmach.F - iterative, whole network, Newton-Raphson solver
- mf???c.F - flow component models
- mfmode.F - alter the iteration parameters, force
use of alternative stack pressure calculation model or
a different matrix solver or toggle trace options.
- mfsbld.F mfsplt.F mfsbps.F - module-specific calling points
Primary variables
- COMMON/?? - under construction
Issues arising
- Applicability of the pressure coefficient sets and
component models
- Use of networks to represent circulating flows
(zonal modelling)
- Numerical stability for tightly coupled problems
- Links with CFD domains can be unstable
Last edited April 2005