Investigation of Water-spray Cooling of Turbine Blades in a Turbojet Engine

An analytical and experimental investigation was made with a J33-A-9 engine to determine the effectiveness of spray cooling as a means of increasing thrust by permitting engine operation at inlet-gas temperatures and speeds above rated. With the assumption of adequate spray cooling at a coolant-to-gas flow ratio of 3 percent, calculations for the sea-level static condition indicated a thrust may be achieved by engine operation at an inlet-gas temperature of 2000 degrees F and an overspeed of 10 percent. Of the water-injection configurations investigated experimentally, those located in the inner ring of the stator diaphragm provided the best cooling at rated engine speed

Fueling China's Rise: Analyzing the Determinants of China's Foreign Energy Investments

I analyze the determinants of China’s foreign energy investments during the period 2001 to 2014. These investments include mergers and acquisitions and portfolio investments as well as loans. My analysis is done at the country level. I consider the effects of factors suggesting motives of market access (such as GDP and Chinese FDI), efficiency/cost reduction (such as GDP growth and per-capita GDP), access to energy resources (such as oil and natural gas reserves) and building political support (such as the presence of arms trade). I estimate the determinants of investment using a Tobit model with random effects, a two-stage Heckman Selection model, and Two-Stage Least-Squares (2SLS) simultaneous equations. I find that Chinese investors take into account considerations of securing access to energy resources, primarily oil, and building political support for China internationally, in tandem with their commercial motives to secure market access and reduce costs. For the largest investments, the motive to secure long-term control over oil supplies is especially strong.Bachelor of Art

NACA Research Memorandums

"An analytical and experimental investigation was made with a J33-A-9 engine to determine the effectiveness of spray cooling as a means of increasing thrust by permitting engine operation at inlet-gas temperatures and speeds above rated. With the assumption of adequate spray cooling at a coolant-to-gas flow ratio of 3 percent, calculations for the sea-level static condition indicated a thrust may be achieved by engine operation at an inlet-gas temperature of 2000 degrees F and an overspeed of 10 percent. Of the water-injection configurations investigated experimentally, those located in the inner ring of the stator diaphragm provided the best cooling at rated engine speed" (p. 1)

NACA Research Memorandums

Report presenting analytical methods to calculate average and local turbine-blade temperatures. The temperatures were compared with experimental data obtained in a forced-convection, water-cooled aluminum turbine over a range of turbine-inlet-gas temperatures and coolant-mass velocities. Results regarding comparison of calculated and experimental aluminum turbine blade temperatures, comparison of calculated and experimental stationary-blade temperatures, stationary water-cooled blade operating data, and turbine operating data are provided

A machine vision platform for measuring imbibition of maize kernels: quantification of genetic effects and correlations with germination

Abstract Background Imbibition (uptake of water by a dry seed) initiates the germination process. An automated method for quantifying imbibition would enable research on the genetic elements that influence the underlying hydraulic and biochemical processes. In the case of crop research, a high throughput imbibition assay could be used to investigate seed quality topics or to improve yield by selecting varieties with superior germination characteristics. Results An electronic force transducer measured imbibition of single maize kernels with very high resolution but low throughput. An image analysis method was devised to achieve high throughput and sufficient resolution. A transparent fixture held 90 maize kernels in contact with water on the imaging window of a flatbed document scanner that produced an image of the kernels automatically every 10 min for 22 h. Custom image analysis software measured the area A of each indexed kernel in each image to produce imbibition time courses. The ultimate change in area (ΔA) ranged from 19.3 to 23.4% in a population of 72 hybrids derived from 9 inbred parents. Kernel area as a function of time was fit well by $$A\left( t \right) = A_{f} \left( {1 - e^{ - kt} } \right)$$ At=Af1-e-kt where A f is the final kernel area. The swelling coefficient, k, ranged from 0.098 to 0.159 h−1 across the genotypes. The full diallel structure of the population enabled maternal genotype effects to be assessed. In a separate experiment, measurements of kernels of the same 25 inbreds produced in three different years demonstrated that production and storage variables affected imbibition much less than genotype. In a third experiment, measurements of 30 diverse inbred lines showed that k varied inversely with germination time (r = − 0.7) and directly with germination percentage (r = 0.7). Conclusions Nonspecialized imaging hardware and custom analysis software running on public cyber infrastructure form a low-cost platform for measuring seed imbibition with high resolution and throughput. We measured imbibition of thousands of kernels to determine that genotype influenced imbibition of maize kernels much more than seed production and storage environments. In some hybrids, k depended on which inbred parent was maternal. Quantitative relationships between k and germination traits were discovered