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Articles by A.L. Tamiru
Total Records ( 3 ) for A.L. Tamiru
  A.L. Tamiru , F.M. Hashim and C. Rangkuti
  This study presents the result of an attempt to develop compressor and turbine maps for a 5.2 MW rated industrial gas turbine. The research is motivated by the need to study load accepting and load rejection characteristics of cooperating gas turbines. Only overall performance parameters of the gas turbine are provided by the manufacture and that made it difficult to carry out such studies. This work proposes the use of scaling method in the fixed geometry region and stage-stacking method in the variable geometry region. Generalized stage and overall component performance curves, all from literature, are used in presenting the performance maps. Characteristics of compressors whose actual maps are known are first used to choose a reference map. Relying on the selected map, predicted performance curves are obtained for the aforesaid gas turbine. The variable geometry is demonstrated considering actual data from literature. Having the design point parameters from limited overall performance data, the proposed approach has managed to get the key performance maps. The results can be used for stability, performance optimization and condition monitoring studies.
  M. Amin A. Majid , A. Zainuddin and A.L. Tamiru
  Performance analysis, optimization and environmental load assessment of an absorption system requires accurate but simplified models. The objective of the present study is to develop such models based on non-dimensional parameters (part load ratio, part-load factor and diverter damper position) and ordinary least squares. Since for the case study, the hourly, daily and monthly load demands data are available, the method of averaging over eight years is considered. The models are developed for a system comprised of two heat recovery steam generators and two steam absorption chillers. It was observed that the proposed method is effective in providing better picture of the relationships between the supplied heat and the amount of energy recovered by each subsystem. The maximum cooling load experienced by the two chillers was about 2392RT, which is 4.32% lower than the design capacity. The steam generators were found operating at part load ratio of about 0.41 only. Both chillers deteriorated in performance within the study period. This was confirmed by the part load ratio of 0.8 and steam consumption higher than that required for a new chiller. A generalized model was also identified for the two chillers with the correlation coefficient (R2), chi-square (χ2) and Root Mean Squared Error (RMSE) equals to 0.9996, 1.9765e-5 and 0.0044, respectively. The model was found accurate for cooling water temperatures in the range of 29 to 32°C.
  M. Amin A. Majid , Shaharin A. Sulaiman , Hamdan Mokhtar and A.L. Tamiru
  As part of a tri-generation plant, an absorption process provides the means to recover the energy that otherwise would be lost to the environment. Since the overall efficiency relies on the amount of energy recovered in all subsystems, knowing the current performance of the absorption process is vital to proper management of the resources. This study proposes the use of data clustering technique to estimate the most frequent operating point experienced by the absorption system in a given year. The same technique is applied to identify operating point trajectory of the system over nine years. In order to demonstrate applicability of the proposed approach, an absorption system that is comprised of two 12 ton h-1 heat recovery steam generators and two 1250 RT double-effect LiBr-H2O steam absorption chillers is considered as a case study. It was observed that data clustering technique is an effective method in establishing the relationships between the supplied heat and the amount of energy recovered by each subsystem. The heat recovery steam generators were identified as operating at part load ratio of about 0.41. The clustering method clearly revealed that both chillers deteriorated in performance. The absorption systems were mostly run at part load ratio of about 0.8. As such, at this operating point the energy demand was by 43% higher than that required for a healthy system. The proposed technique is applicable for performance monitoring, optimization and multi-state reliability studies of the absorption system.
 
 
 
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