Prof. Constantin Mihaela
Thermodynamics, University Politehnica of Bucharest, Bucharest, Bucureşti, Romania
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Academic Career Length
16Years (2011-Present)
(Calculated once Scilit publication data is synced: current year − year of first publication + 1)
Representative Publications
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Journal Article
The transition towards a sustainable and renewable energy future is essential to mitigate climate change and reduce greenhouse gas emissions. Small–medium combined heat and power (CHP) systems are increasingly popular for distributed energy generation, as they offer improved energy efficiency and reduced emissions compared to traditional power generation systems. This article reviews recent research articles related to small–medium CHP systems, including their role in renewable energy systems, use of biofuels, steam injection, diagnostics, and carbon capture. Throughout the research, the high potential of coastal regions has been observed and studied as a solid base for the later development of CHP systems. Based on the reviewed literature, the highest potential solutions are proposed to be further investigated as an efficient, economical solution for generating electricity and heat for various small-scale applications.
Journal Article
CDCatalina Dobre
Catalina Dobre
Lavinia GROSUMCMonica Costea
Monica CosteaConstantin MihaelaThe paper presents experimental tests and theoretical studies of a Stirling engine cycle applied to a β-type machine. The finite physical dimension thermodynamics (FPDT) method and 0D modeling by the imperfectly regenerated Schmidt model are used to develop analytical models for the Stirling engine cycle. The purpose of this study is to show that two simple models that take into account only the irreversibility due to temperature difference in the heat exchangers and imperfect regeneration are able to indicate engine behavior. The share of energy loss for each is determined using these two models as well as the experimental results of a particular engine. The energies exchanged by the working gas are expressed according to the practical parameters, which are necessary for the engineer during the entire project, namely the maximum pressure, the maximum volume, the compression ratio, the temperature of the heat sources, etc. The numerical model allows for evaluation of the energy processes according to the angle of the crankshaft (kinematic–thermodynamic coupling). The theoretical results are compared with the experimental research. The effect of the engine rotation speed on the power and efficiency of the actual operating machine is highlighted. The two methods show a similar variation in performance, although heat loss due to imperfect regeneration is evaluated differently.
Journal Article
CDCatalina Dobre
Catalina DobreLavinia GROSU
Alexandru DobrovicescuCGChisiu Georgiana
Chisiu GeorgianaConstantin MihaelaThe purpose of the study is to show that two simple models that take into account only the irreversibility due to temperature difference in the heat exchangers and imperfect regeneration are able to indicate refrigerating machine behavior. In the present paper, the finite physical dimensions thermodynamics (FPDT) method and 0-D modeling using the Schmidt model with imperfect regeneration were applied in the study of a β type Stirling refrigeration machine.The 0-D modeling is improved by including the irreversibility caused by imperfect regeneration and the finite temperature difference between the gas and the heat exchangers wall. A flowchart of the Stirling refrigerator exergy balance is presented to show the internal and external irreversibilities. It is found that the irreversibility at the regenerator level is more important than that at the heat exchangers level. The energies exchanged by the working gas are expressed according to the practical parameters, necessary for the engineer during the entire project. The results of the two thermodynamic models are presented in comparison with the experimental results, which leads to validation of the proposed FPDT model for the functional and constructive parameters of the studied refrigerating machine.
1 October 2013 in Applied Mechanics and Materials
Journal Article
In the paper the differential equation of the transfer speed of the oxygen towards water is numerically integrated, software is written and theoretical results are presented. A setup for experimental tests regarding the functioning of fine bubble generators was designed and built in the frame of the Department of Thermotechnics, Engines, Thermic and Refrigeration Plants laboratory. Measurements regarding the increase of the concentration of oxygen dissolved in water were performed. Theoretical and experimental results were compared.
Journal Article
This paper presents the mathematical modeling of the oxygen transfer process using partial differential equations (PDEs). This process is crucial in various environmental and engineering applications, such as wastewater treatment, aeration systems, and natural water bodies, in order to maintain water quality. The authors solved the typical PDE for describing the change in oxygen concentration over time and present the developed model of the differential equation with the term “source”, indicating that the model could be used to optimize oxygen transfer in various environmental and engineering applications, contributing to improved water quality and system efficiency.
15 July 2019 in Revista de Chimie
Journal Article
NBNicolae Baran
Nicolae Baran
Constantin MihaelaBTBeatrice Tanase
Beatrice Tanase
EMEdgar Moraru
Edgar Moraru
CMCorina Ioana Moga
Corina Ioana Moga
The paper presents two constructive solutions in the field of fine bubble generators that serve to aerate the water. Two installations for experimental researches have been designed and built in connection with the two constructive solutions. The dissolved oxygen concentration was experimentally determined. The theoretical and experimental results for the two constructive solutions are compared showing a good coincidence in relation to the results reported in the literature.
About Me
Ionela Mihaela Constantin is a Senior Lecturer and PhD Engineer at the University POLITEHNICA of Bucharest, Faculty of Mechanical Engineering and Mechatronics. Her teaching and research activities focus on technical thermodynamics, numerical methods, computer programming, and gas dynamics, combining a strong academic background with applied research and project evaluation expertise. With over fifteen years of professional experience, she has developed a multidisciplinary career that bridges engineering, digital innovation, and environmental sustainability. She also plays an important role as an Evaluator and Technical Expert for several national programs. She collaborates with the Executive Agency for Higher Education, Research, Development and Innovation Funding (UEFISCDI) and the Ministry of Energy, assessing funding applications for renewable energy and research projects. As a Technical Expert and Horizontal Principles Evaluator for POCIDIF and PoS 2021–2027, through TEAMPRO Strategy Consulting, she contributes to ensuring quality and sustainability standards in innovation-driven investments. In parallel, she acts as a Helpdesk Expert within the Ministry of Education, supporting the national program “RECRED – New Regulations for a Relevant and Open Curriculum.” Her academic record includes five monographs and a collection of applied exercises, along with over 20 scientific papers published in ISI- and Scopus-indexed journals, 15 of which are indexed in Web of Science.
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