Application of a pre-combustion chamber (PCC) ignition system is one of the methods to improve combustion stability and reduce toxic compounds emission, especially NO_x. Using PCC allows the operation of the engine at lean combustion conditions or the utilization of low calorific gaseous fuels such as syngas or biogas. The paper presents the results of an experimental study of the combustion process in two stroke, large bore, stationary gas engine GMVH 12 equipped with two spark plugs (2-SP) and a PCC ignition system. The experimental research has been performed during the normal operation of the engine in an industrial compression station. It was observed that application of PCC provides less cycle-to-cycle combustion variation (more than 10%) and nitric oxide and carbon monoxide emissions decreased to 60% and 26% respectively. The total hydrocarbon (THC) emission rate is 25% higher for the engine equipped with PCC, which results in roughly two percent engine efficiency decrease. Another important criterion of engine retrofitting was the PCC location in the engine head. The experimental results show that improvement of engine operating parameters was recorded only for a configuration with one port offset by 45° from the axis of the main chamber. The study of the ignition delay angle and equivalence ratio in PCC did not demonstrate explicit influence on engine performance.

The paper presents the results of numerical analysis of a wind panel built of 6 vertical Savonious wind turbines. The basis for comparison were calculations made for a single turbine with the same parameters. Simulations were performed for six different directions of inflow, from almost parallel to the panel (5◦) to almost perpendicular (85◦). The calculations were performed using the Ansys FLUENT program, while the computational grids were prepared in the GMSH program. The aim of the analyses was to investigate the influence of the wind inflow angle on the panel on the amount of energy produced on subsequent turbines. The analysis covered the velocities between individual turbines and their influence on subsequent turbines. The calculations were performed as time-varying on a two-dimensional plane. Based on the obtained results, it was found that the inflow angle has a large influence on the efficiency of subsequent turbines. For the angles up to 30◦ the aerodynamic wake behind subsequent turbines has a huge influence on the stability of the inflow on the next ones. For the cases from 45◦ the flow between turbines starts playing significant role.

The paper presents the results of numerical analyses of a wind panel built of 6 vertical Savonious wind turbines. The basis for comparison were calculations made for a single turbine with the same parameters. Simulations were performed for six different directions of inflow, from almost parallel...