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Problem-based learning and entrepreneurially minded learning modules have been developed to include fluid power concepts into undergraduate Mechanical Engineering core courses Thermodynamics and Fluid Mechanics. Modules in Thermodynamics focus on pneumatics and modules in Fluid Mechanics focus on hydraulics. The purpose of this work is to assess the created modules for student awareness of fluid power,...
During the heat transfer, due to temperature differences, a share from the heat exergy content is destroyed. Consequently, the use of heat exchangers in thermodynamic cycles declines their efficiencies. The paper presents an original model for computing the exergy destruction during the heat transfer in a superheated steam generator. The model was applied for a Concentrated Solar Plants with molten...
Thermal systems are being encountered in nearly all the engineering fields like heat exchangers, energy storage systems, pumps and pipe networks etc. Entropy generation analysis based on second law of thermodynamics is thus a natural want for the optimization of thermodynamic efficiency of engineering flow configurations including those involving porous medium like the one which has been modeled in...
In the present study, the most important parameters that affect the performance of a solar chimney power plant are investigated. The plant has a collector area of 7000 m diameter and a tower of 1000 m height. Under certain weather conditions, the results obtained show that the maximum electrical power of this plant can be reached in June and can be up to 119 MW. This amount of electrical power, which...
This paper discusses gasification of organic municipal solid waste in Lebanon for electricity production. Therefore, a mathematical model is performed on Matlab to maximize system performance by studying the temperature, humidity and optimal oxygen intake. Residual heat from the syngas obtained is recovered, conveying thermal energy feed into an Organic Rankine Cycle (ORC). For this, an ORC is modeled...
This paper is concerned with the energy and exergy analyses of flat plate solar collectors in transient behavior. Using the first law of thermodynamics, energy analysis was carried to estimate the amounts of energy gained from solar water collectors and the ratios of energy utilization. However, exergy analysis was accomplished to determine the location, type, and magnitude of exergy losses during...
In this study, low temperature Organic Rankine Cycle (ORC) systems with single and two-stage turbine are proposed for the production of electricity. The refrigerant R-134a is selected as working fluid based on peak temperature of the cycle for solar and geothermal applications. The design criteria of ORC system is introduced and explained in detail. The radial inflow turbine is selected to satisfy...
In fluid treatments of plasma-wall-transition (PWT) problems, the system of fluid equations of a given particle species is often1−3 closed by means of an equation of the form Dp/Dt = (γp/n) Dn/Dt (“local polytropic law”), where n(x⃗, t) and p(x⃗,t) are the density and pressure, γ(⃗x,t) is called the “polytropic-coefficient function (PCF)”3, and D/Dt = ∂/∂t + ⃗u · ∇ is the Lagrangian time derivative...
Complex plasma is the so called plasma state of soft matter. It is usually comprised of low temperature gas discharge and dust, often called dusty plasma. In our laboratory experiments we use capacitively coupled radio frequency (rf) discharges in noble gasses into which we inject mono disperse spherical particles which are a few micrometers in diameter. These particles charge up negatively and their...
Based on the theories of variable-mass system thermodynamics and viscous fluid mechanics, the steam charging process of the steam accumulator charge system was studied,the mathematic model of the system was built up.Then the variable operating status characteristics which include the change of action time parameter of control valve and the load were simulated based on Simulink of Matlab,some meanful...
This paper presents a review of the status of power generation with nonaqueous working fluids from low-temperature thermal resource, the features, equipment composition and working processed as well as comparison of two main types of thermodynamic cycles which are Organic Rankine Cycle(ORC) and Kalina Cycle and nonaqueous working fluids including their classification and filter criteria for thermodynamic...
For computer simulations on fluid phase equilibrium calculations, an important issue is to determine the unlike pair interaction parameter between unlike components, which is at present determined by a trial-and-test method or by laborous iterative calculations. In this work, basing on the thermodynamic scaling method put forward and developed by Graham, Valleau and Kiyohara etc, we propose a new...
The objective of this study is to analyze the effects of heat loss and variable specific heats of working fluid on the performance of an Atkinson engine by using finite-time thermodynamics. The variations in power output and thermal efficiency with compression ratio, and the relations between the power output and the thermal efficiency of the cycle are presented. The results show that the power output...
The purpose of this study is to analyze the effects of variable specific heats of working fluid on the performance of a Dual engine with considerations of heat transfer and friction by using finite-time thermodynamics. The results show that the power output as well as the efficiency where maximum power output occurs will increase with increasing the amount of heat added to the engine due to combustion...
Three working fluids R125, R143a and R32 were analyzed thermodynamically for the transcritical heat pump with low temperature geothermal source as its heat source. The system parameters investigated include coefficient of performance (COP), volumetric heat capacity (Qv), compressor discharge temperature and the pressure ratio. The results show that Qv, pressure ratio and compressor discharge temperature...
This paper has investigated the PT equation of state for the new environmental-friendly refrigerant R600a, and on this basis, the mathematical model of heat pump with regenerator internal heat exchanger is constructed. After systematical calculating and analyzing the cycle performance of the heat pump charged with R600a and several types under standard operating condition and variable operating conditions,...
A software on computational fluid dynamics,FLUENT, is introduced to simulate the oscillating characteristics in the parallel plate fold regenerator. Results show that for a specific point, pressure oscillations with the change of time is sinusoidal or cosine waveform, and due to the periodic oscillation of pressure, the temperature and velocity periodically changing around the balance point, the variation...
With the utilisation of binary mixture as working fluid in a power generation cycle, higher heat conversion rate will be achieved in the boiler which results in more efficiency. In this paper two kalina cycle designs using binary mixtures as working fluid were compared, the cycle efficiency as a function of turbine inlet and separator outlet were calculated for the kalina cycles. The cycle's property...
A comparative study of different Cases (A1, A2, B, C1, C2, D) of regenerator calculating methodology has been carried out for use in subcritical and transcritical organic Rankine cycles(ORCs) driven by low-temperature heat sources. The applicable ranges and conditions as well as influences on thermodynamic performances of different Cases have been analyzed. Results show that, for subcritical ORCs...
Environmental conservation issue advances the refrigerant substitute for the Freons. Natural working fluid must be a perfect choice. Therefore, natural friendly refrigerants R744 and R600a are selected in this research to be a binary mixture. Such a mixture can weaken their shortcomings by decreasing high heat rejection pressure as that of pure R744, and reducing flammability as that of pure R600a...
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