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Contenido archivado el 2022-12-27

RANKINE CYCLE IMMERSED ENERGY SOURCE WITH HIGH-PRESSURE COMBUSTION CHAMBER AND CONSTANT MASS OPERATION

Objetivo

The main objective of the current project is the tuning-up of a 60 bar aeronautical combustion chambre with a thermal power of 400 kW, working with methanol and oxygen and cooled by injection of combustion products at 25 deg. C. In the future, this new combustion chamber is to be the heat generation device of a Rankine cycle power module using an organic fluid. By working at high pressure (60 bar), the combustion products can be condensed in a sea water cooled heat-exchanger and stored in a tank so that no exhaust is required and the module mass is constant. So, this means there is no diving depth limit for such an energy source.
Calculation and design
a) Design
The design of the chamber was carried out using iterative calculations with several independent codes: drop size distribution, pressure drops, adiabatic gas temperature, combustion kinetics, and wall temperatures were calculated. These first iterative calculations resulted in the sizing of the chamber. A 3D reactive flow code, FLUENT, was used to validate the sizing and provide more information about internal flows: recirculating zones, cooling films, dilution jets, droplet trajectories, and local wall and gas temperatures were studied.
b) Atomization tests:
Atomization tests under high pressure (60 bar) were carried out on a specific test bench. Comparison between experimental and calculation results (droplet diameter and trajectory, spray geometry) permitted the design and validation of nozzle geometry.
c) Ignition trials
A number of ignition trials were performed at various mass flowrates and pressures (1/4 to 1/2 of full power, 5 to 20 bar). Areduced dilution rate is needed for successful ignition and the CO2 flowrate has to be increased rapidly just after ignition to maintain a wall temperature of less than 900 deg.C.
d) Combustion trials
Combustion trials at various thermal powers (80 to 400 kW, 60 bar) were successfully carried out, giving the following results :
- combustion is quite stable and silent
- wall cooling is more efficient at high power than at reduced power (maximum wall temperature is about 900 deg. C at 100 kW and about 700 deg. C at 400 kW)
- combustion efficiency, for which the calculations are based on gas analysis measurement data, is better than 0.997 as soon as the oxygen excess is more than 7 % at 100 kW and 9 % at 400 kW.
In conclusion, the technical programme was carried out progressively and successfully. A new project consisting in the constructing of a sealed Rankine has been underway at Societe BERTIN since mid 1988. The next step in the development of the global engine will be to fit a high pressure heat generation loop and to couple it with the Rankine cycle.
The project began in July 1985 and had a 3 year duration. It was divided into 4 phases :
PHASE 1: Design, sizing of the combustion chamber. Construction drawings, procurement and fabrication of each component of the test bench.
PHASE 2: Erection of test facilities: combustion chamber, fluids circuits, electrical circuits for control, regulation and safety. Implementation of a data acquisition programs for measurement and control.
PHASE 3: Tests of the combustion chamber including injection, ignition, thermal behaviour, flame stability, combustion efficiency and control under various operating conditions.
PHASE 4: Synthesis and integration
The final report gives the progress of the work and a synthesis of the results. the integration of the chamber into the global system is examined for various ranges of power corresponding to future industrial needs.
The main characteristics of the combustion chamber are:
- nominal thermal power = 400 kW
- mass flowrates= 20 g/s methanol
= 30 g/s oxygen
= 335 g/s carbon dioxyd
- tube flame = 0.132 m length
= 0.062 m diameter
- operating pressure = 6MPa
- specific power = 20 MW/m3/atm
- range of working power = 20 to 120 %
- injection by a pneumatic nozzle
- flame stability induced by a swirl at the oxygen inlet
- cooling of the tube flame by external flow and film cooling of CO2
- dilution of the combustion gases by injection of cold CO2
- ignition by a plasma spark plug and flame control by a photoelectric cell
- internal pressure maintained by a sonic valve during the open loop
combustion tests.
See also project TH./13009/87/FR

Convocatoria de propuestas

Data not available

Régimen de financiación

DEM - Demonstration contracts

Coordinador

Bertin & Cie
Aportación de la UE
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Dirección
59 rue Pierre Curie Zone Industrielle des Gatines
78373 Plaisir
Francia

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Coste total
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