A comparison of fluid and heat control concepts for a binary Rankine cycle solar dynamic space power system

Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Aeronautics and Astronautics, 1988.Bibliography: leaves 103-104.by Seung Jin Song.M.S

Analysis of Building Energy Savings Potential for Metal Panel Curtain Wall Building by Reducing Thermal Bridges at Joints Between Panels

AbstractTo achieve national greenhouse gas reduction in the building sector, heating and cooling energy in buildings should be reduced. The government has strengthened regulations on insulation performance for building energy savings. However, the building envelope has various thermal bridges. In particular, a metal panel curtain wall comprises a number of thermal bridges at joints between the panels and the fixing units, thus degrading the overall thermal performance. To reduce building energy, it is necessary to reduce thermal bridges in building envelopes. This study aims to analyze the energy saving potential achieved by reducing thermal bridges. For this, the insulation performance and building energy needs of the existing and alternative metal panel curtain wall were evaluated. The alternative metal panel curtain wall that uses plastic molds at joints between panels and the thermally-broken brackets was suggested to reduce heat loss through thermal bridges. As results, the effective U-value of the alternative metal panel curtain wall was reduced by 72% compared with the existing metal panel curtain wall. In addition, annual heating energy needs of the alternative metal panel curtain wall building was reduced by 26%, and annual total energy needs was reduced by 6% because annual cooling energy needs of it slightly increased compared with the existing metal panel curtain wall. In conclusion, the alternative metal panel curtain wall considerably influenced the savings in building energy needs by reducing thermal bridges

GT2008-50479 A TIME-DOMAIN FLUID-STRUCTURE INTERACTION ANALYSIS OF FAN BLADES

ABSTRACT This paper presents aerodynamic and aeromechanical analyses for an entire row of fan blades (i.e. tens of blades with a finite aspect ratio) subject to a uniform incoming flow. In this regard, a new unsteady three-dimensional vortex lattice model has been developed for multiple blades in discrete time domain. Using the new model, the characteristics of the unsteady aerodynamic forces on vibrating blades, including their temporal development, are examined. Also, the new aerodynamic model is applied to examine the aeromechanical behavior of fan blades by using a standard eigenvalue analysis. For this analysis, the fan blades have been modeled as threedimensional plates, and, increasing the number of blades (or solidity) is predicted to destabilize the fan blade row. INTRODUCTION Fluid-structure interaction phenomena occur in many scientific and engineering applications, including aircraft wings and turbomachinery blades. Understanding fluid structure interactions in turbomachinery is important because such interactions lead to fatigue and ultimately structural damage of blades. The fluid structure interaction analyses require modeling of unsteady aerodynamics which can be conducted in either time or frequency domain. In the time domain analyses, Euler and Navier-Stokes solvers are used to calculate unsteady aerodynamic forces on turbomachinery blades. At each time step, for a given geometry, the flow field is solved to determine the aerodynamic forces acting on the blades. Subsequently, the forces are used to analyze the blades' motions and update their displacements. The entire process is then repeated. Such time domain analyses require extensive computation time and cost [1,2]. On the other hand, unsteady aerodynamic analysis can also be carried out in the frequency domain, and the frequency domain approaches have been applied to calculate unstead

Empirical Validation of Heat Transfer Performance Simulation of Graphite/PCM Concrete Materials for Thermally Activated Building System

To increase the heat capacity in lightweight construction materials, a phase change material (PCM) can be introduced to building elements. A thermally activated building system (TABS) with graphite/PCM concrete hollow core slab is suggested as an energy-efficient technology to shift and reduce the peak thermal load in buildings. An evaluation of heat storage and dissipation characteristics of TABS in graphite/PCM concrete has been conducted using dynamic simulations, but empirical validation is necessary to acceptably predict the thermal behavior of graphite/PCM concrete. This study aimed to validate the thermal behavior of graphite/PCM concrete through a three-dimensional transient heat transfer simulation. The simulation results were compared to experimental results from previous studies of concrete and graphite/PCM concrete. The overall thermal behavior for both materials was found to be similar to experiment results. Limitations in the simulation modeling, which included determination of the indoor heat transfer coefficient, assumption of constant thermal conductivity with temperature, and assumption of specimen homogeneity, led to slight differences between the measured and simulated results

Elastic p-12C scattering by using a cluster effective field theory

The elastic p-12C scattering at low energies is studied by using a cluster effective field theory (EFT), where the low-lying resonance states (s1/2, p3/2, d5/2) of 13N are treated as pertinent degrees of freedom. The low-energy constants of the Lagrangian are expressed in terms of the Coulomb-modified effective range parameters, which are determined to reproduce the experimental data for the differential cross-sections. The resulting theoretical predictions agree very well with the experimental data. The resulting theory is shown to give us almost identical phase shifts as obtained from the R-matrix approach. The role of the ground state of 13N below the threshold and the next-to-leading order in the EFT power counting are also discussed.Comment: 17 pages, 6 figure

Cutting-edge Technologies to Achieve a Higher Level of Modular Construction – Literature Review

Cost overruns, schedule delays, and a shortage of skilled labor are common problems the construction industry is currently experiencing. Modularization and standardization strategies have the potential to resolve the various problems mentioned above and have been applied for various construction applications for a long time. However, the level of modularization remains low, and modular construction projects have not been getting the full benefits. Thus, this review investigated the cutting-edge technologies currently being utilized to develop the modular construction field. For this paper, qualified research papers were identified using predetermined keywords from previous related research papers. Identified literature was then filtered and analyzed. According to the included reviews, several technologies are being developed for modular construction. For example, automated design and monitoring systems for modularization were developed. In addition, research labs are utilizing robotic arms for modular construction to achieve a high level of completion in the construction industry, as is seen in the manufacturing industry. Despite these efforts, more research and development are necessary because some automation technologies still require manual activities. Thus, there is great potential for further development of modularization techniques, and further research is recommended to achieve high levels of modularization