PIPELIQ - Pressure and Mass Flow Balance in Hydraulic and Liquid Systems

Applications

Calculating pressure drops in piping networks
Calculation of hydraulic balances (pressure and mass flow) in hydraulic systems
Support in the sizing and selection of equipment (pumps, valves, pipes, etc.).
Heat balances in non-compressible circuits
Operation and control systems of non-compressible circuits: cooling loops and heat pipes with no phase change.

Status Commercial toolkit, available for sale and project development

Last Releases

Description

PIPELIQ is a toolkit designed to perform balancing of pressures and mass flow of hydraulic/liquid systems. The toolkit considers thermal delay and thermal storage allowing the analysis of slow thermo-fluid transients. Moreover the user can design and tune the control loops of the fluid system due to the fact that fluid actuators and sensors can be connected to control elements.

The PIPELIQ toolkit provides a set of components to represent 1-D liquid flow networks. It enables the user to easily build typical simulation models of cooling and heating loops including the control system and to perform steady state, parametric studies and thermal transient studies of these models thanks to the powerful features of the EcosimPro/PROOSIS experiment.

This library can be used for different applications mainly focused on:

Performing hydraulic balancing of pressures and mass flow
Sizing and selection of equipment (pump, valves, pipes, etc)
Thermal balances and thermal transient studies of 1-D liquid networks

Features

The working fluid is a liquid which properties are calculated as function of the temperature
Pressure loss in pipes and fittings are calculated using steady state correlations for pressure loss. Laminar and turbulent flow transition is taken into account
Reverse flow
Thermal storage in the fluid and solid walls of components
Thermal delay due to convective transport can be simulated by nodalization of the pipes into multiple control volumes
Hydrostatic pressure difference and natural circulation
The simulation models can be connected to MS Excel

Limitations: PIPELIQ library does not consider the following phenomena:

Two-phase flow overall as a result of boiling or fast drops in pressure
Pressure waves (water hammer)
Cavitation in valves and orifices
Cavitation in pumps (a warning message is displayed when cavitation conditions are reached)

User Cases

Flow distribution of an Essential Service Water System of a Nuclear Power Plant

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The model of this system was connected to MS Excel spreadsheet in order to easily report analyses changing the following parameters:

Positions of the valves
Thermal loads of the equipments
Boundary conditions of the system (temperature, etc)

Low pressure feed water system of a Combined Cycle Power Plant

The model represents the low pressure feed water system of a combined cycle power plant. The model includes two pumps in parallel (the running one and the spare one) that provides water to the suppliers. Both pumping trains consider the minimum circulating flow and the attemperation water flow is regulated with a PI controller.

The schematics diagram of the simulation model is depicted in the following figure. This model shows the capability to include control logics of the hydraulic system.

The scenario analyses the start-up of one of the pump according to a predefined start-up curve and the required attemperation water flow as a function of time using look-up tables.

The following plots show the evolution of the water flow supplied by the pump, the attemperation water flow, the behavior of the control loop and the position of the control valve during the start-up of the pump.

As the required mass flow across the atemperation line is greater, the valve is gradually opened as depicted in the following figure.