Computer-Aided Simulation of the Volumetric Efficiency of a 2 MW Gas Engine

A phenomenological base semi-physical thermodynamic model for the cylinder and exhaust manifold of a natural gas 2-megawatt four-stroke internal combustion engine

“…Although the focus of this work is associated with the cylinder and engine exhaust sections, the first three steps of the methodology are identical to a model generated for the mathematical and thermodynamic representation of the intake section of the same engine. Therefore the first two steps and part of the third of the previously chosen methodology [27] and the general information of the engine, will be referenced from previous work [27]. The natural gas composition in this location is 97.97% CH 4 , 1,5% N 2 , 0.1626% CO 2 , 0.2559% C 2 H 6 , 0.0516% C 3 H 8 , 0.0207% C 4 H 10 (i-butane), 0.0083% C 4 H 10 (n-butane), 0.0076% C 5 H 12 (i-pentane), 0.0021% C 5 H 12 (n-pentane) and 0.0132% C 6 H 14 (n-hexane) with a pressure line comprised between 1152 bar at 1211 bar.…”

“…Taking into account the previous relevant information [27], the questions that the model will answer will be the following ones:¿How does heat transfer affect the effective efficiency and the mean effective pressure of the engine?¿How does the cylinder outlet temperature, and the inlet temperature of the compressor of the turbocharger influence the outlet temperature of the turbine?…”

“…Once the model objective is defined, the mass and energy conservation principles are applied to each subsystem of interest [27], according to the following considerations:The intake and exhaust manifolds are considered as reservoirs of thermal energy, with output properties equal to those of the control volume.The two systems of turbochargers are unified in a single system, which will be modeled as a single stage of expansion in the exhaust.One cylinder is studied, and it is assumed that its behavior is the same for the other cylinders, where the exhaust gas output properties will be the same as those contained within it.…”

“…Since is only desired average values or values from mass and energy balances of simplified engine sub-systems [12, 13], this to facilitate future engine control and observation applications [14, 15] in real time. In the development of the mathematical description of the engine, more opts for MVEM [23, 24, 25, 26, 27, 28, 29], this type of modeling does not present high complexity compared to those of cylinder per cylinder, however, allow to obtain results of the macroscopic behavior of the engine, and its component [3, 12, 16] and [17]. Hendricks, in 1990 [12], developed an MVEM in an ICE by provoked ignition, with energy balances based on classical thermodynamics, very similar to what is normally implemented today.…”

“…In addition, G. Valencia et al. [27] simulated a semi-physical model by means of fundamental equations to predict the thermal behavior of the engine under study, and the dynamics of the airline of the 2 MW Jenbacher natural gas internal combustion engine is presented, but focused on the engine intake area only, which indicates a limitation of the models with respect to the system parameters that were not analyzed.…”