EVALUASI KEJADIAN KEBAKARAN TAHUN 2019 DI KPH KAYU TANGI RPH PENGARON HUTAN LINDUNG LIANG ANGGANG

The aim of the study was to evaluate the fire incident at 2019 and identify the fuel charge in the Tangi wood RPH KPH from Liang Anggang Forest Reserve. The research location is conducted with the purpose of sampling at 5 points that occur fire incidents and in each tile a fire event created triangular plot made with 3 sizes 30 x 30 x 30 m, 10 x 10 x 10 m, and 1 x 1 m2 systematically. The fire incident was found at five research locations in the area of Liang Anggang protected Forest, consisting of 4 blocks I and 1 region in the Block II area. Plots 1, 2, 4, and 5 have been performed and the fire area is only in the most severe plots, while in the tile 3 the incidence area is very severe because no blackout activities are carried out there. The lost fuel load on block I and Block II in the 2019 is severe and can be categorized in high weather warnings even reaching extreme so that fire prone to fire occurs.Tujuan dari penelitian ini adalah untuk mengevaluasi kejadian kebakaran tahun 2019 dan mengidentifikasi muatan bahan bakar di KPH Kayu Tangi RPH Pengaron Hutan Lindung Liang Anggang. Lokasi penelitian dilakukan secara purposive sampling pada 5 titik yang terjadi kejadian kebakaran dan pada masing-masing petak kejadian kebakaran dibuat plot segitiga yang dibuat dengan 3 ukuran yaitu 30 x 30 x 30 m, 10 x 10 x 10 m, dan 1 x 1 m2 secara sistematis. Kejadian kebakaran ditemukan pada lima lokasi penelitian di areal Hutan Lindung Liang Anggang, yang terdiri dari 4 di wilayah blok I dan 1 di wilayah blok II. Petak 1, 2, 4, dan 5 telah dilakukan pemadaman dan luasan kejadian kebakaran pun hanya pada petak 2 yang paling parah, sedangkan pada petak 3 areal kebakarannya sangatlah parah dikarenakan tidak ada kegiatan pemadaman yang dilakukan disana. Muatan bahan bakar yang hilang pada blok I dan blok II pada tahun 2019 sangatlah parah dan bisa dikategorikan dalam rambu pengukuran cuaca adalah tinggi bahkan mencapai ekstrim sehingga rawan terjadi kebakaran.

Development of a three-zone combustion model for stratified-charge spark-ignition engine

A thermodynamic model for calculating the operating process in the cylinder of a spark-ignition engine with internal mixture formation and stratified air-fuel charge based on the volume balance method was developed. The model takes into account the change in the working fluid volume during the piston movement in the cylinder. The equation of volume balance of internal mixture formation processes during direct fuel injection into the engine cylinder was compiled. The equation takes into account the adiabatic change in the volume of the stratified air-fuel charge, consisting of fuel-air mixture volume and air volume. From the heat balance equation, the change in the fuel-air mixture volume during gasoline evaporation in the fuel stream and from the surface of the fuel film due to external heat transfer was determined. Basic equations of combustion-expansion processes of the stratified air-fuel charge were derived, taking into account three zones corresponding to combustion products, fuel-air mixture and air volumes. The equation takes into account the change in the working fluid volume due to heat transfer and heat exchange between the zones and the walls of the above-piston volume. Dependences for determining the temperature in the three considered zones and pressure in the cylinder were obtained. Graphs of changes in the volumes of the combustion products, fuel-air mixture and air zones with the change of the above-piston volume in partial load modes (n=3,000 rpm) were plotted. With increasing load from bmep=0.144 MPa to bmep=0.322 MPa, at the moment of fuel ignition, the volume of the fuel-air mixture increases from 70 % to 92 % of the above-piston volume. At the same time, the air volume decreases from 30 % to 8 %. Analysis of theoretical and experimental indicator diagrams showed that discrepancies in the maximum combustion pressure do not exceed 5 %

A phenomenological model for the description of unburned hydrocarbons emission in ultra-lean engines

The adoption of lean-burn concepts for internal combustion engines working with a homogenous air/fuel charge is under development as a path to simultaneously improve thermal efficiency, fuel consumption, nitric oxides, and carbon monoxide emissions. This technology may lead to a relevant emission of unburned hydrocarbons (uHC) compared to a stoichiometric engine. The uHC sources are various and the relative importance varies according to fuel characteristics, engine operating point, and some geometrical details of the combustion chamber. This concern becomes even more relevant in the case of engines supplied with natural gas since the methane has a global warming potential much greater than the other major pollutant emissions. In this work, a simulation model describing the main mechanisms for uHC formation is proposed. The model describes uHC production from crevices and flame wall quenching, also considering the post-oxidation. The uHC model is implemented in commercial software (GT-Power) under the form of “user routine”. It is validated with reference to two large bore engines, whose bores are 31 and 46 cm (engines named accordingly W31 and W46). Both engines are fueled with natural gas and operated with lean mixtures (λ > 2), but with different ignition modalities (pre-chamber device or dual fuel mode). The engines under study are preliminarily schematized in the 1D simulation tool. The consistency of 1D engine schematizations is verified against the experimental data of BMEP, air flow rate, and turbocharger rotational speed over a load sweep. Then, the uHC model is validated against the engine-out measurements. The averaged uHC predictions highlight an average error of 7% and 10 % for W31 and W46 engines, respectively. The uHC model reliability is evidenced by the lack of need for a case-dependent adjustment of its tuning constants, also in presence of relevant variations of both engine load and ring pack design.

Oxide Emissions Reduction from Combustion Control in a Diesel Engine

The authors showed that the European Union norms for the toxicity of exhaust gases (Euro 1 – Euro 5) contributed to the reduction of main harmful components emissions by several times. In foreign countries, Stage and Tier regulations applied to tractor equipment, which also limited the content of toxic components at the legislative level.(Research purpose) To reduce the content of nitrogen oxides in exhaust gases by more efficient regulation of the fuel charge distribution in the gas-diesel engine cylinder, changes in the concentration of diesel and gas fuel in certain zones, as well as the use of exhaust gas recirculation.(Materials and methods) The authors analyzed the results of modeling the formation of nitrogen oxides by controlling the workflow in the gas-diesel modification of the diesel engine. In the calculations, the geometric parameters of the D-120 engine, operating at 2000 revolutions per minute, with a filling of 0.6-0.9 volume, were used. The average excess air ratio for the charge was 1.2-3.0, and the excess air ratios for the gas-air mixtures did not exceed 1.2-2.5.(Results and discussion) Using the computational model, the authors estimated the parameters at different pressures at the engine inlet within 0.05-0.09 megapascals, as well as with an increase in the residual gas coefficient in the range of 5-15 percent with a decrease in the concentration of nitrogen oxides from 2500 to 1100 parts per million. Experiments showed that when the power changed from 100 to 20 percent, the nitrogen oxides concentration decreased from 1940 to 800 parts per million.(Conclusions) The authors confirmed the adequacy of the calculation model. They determined that a 40-50 percent reduction in the nitrogen oxide concentration in exhaust gases was achieved with various layering schemes in the combustion chamber. They found that the standards for carbon monoxide, hydrocarbons and nitrogen oxides would require mixed engine regulation. It was proved that recirculation of 15 percent of exhaust gases could reduce nitrogen oxide emissions by another 50 percent.

A Concept for Striking Range Improvement of the GROM/PIORUN Man-Portable Air-Defence System

This paper presents a concept for striking distance performance improvement of the GROM/PIORUN Man-Portable Air-Defence System rocket missiles by increasing the rated diameter of the rocket missile propulsion system and its fuel charge weight. A mathematical and physical model of the GROM rocket missile was designed and its enhanced propulsion system was simulated in a computer environment. The computer simulation results were displayed on plot charts.