Single stage experimental evaluation of compressor blading with slots and vortex generators. Part 2 - Data and performance for stage 5 without slots or vortex generators

Comparison performance data of compressor blading without slots or vortex generator

Single-stage experimental evaluation of tandem-airfoil rotor and stator blading for compressors, part 8

An experimental investigation was conducted with an 0.8 hub/tip ratio, single-stage, axial flow compressor to determine the potential of tandem-airfoil blading for improving the efficiency and stable operating range of compressor stages. The investigation included testing of a baseline stage with single-airfoil blading and two tandem-blade stages. The overall performance of the baseline stage and the tandem-blade stage with a 20-80% loading split was considerably below the design prediction. The other tandem-blade stage, which had a rotor with a 50-50% loading split, came within 4.5% of the design pressure rise (delta P(bar)/P(bar) sub 1) and matched the design stage efficiency. The baseline stage with single-airfoil blading, which was designed to account for the actual rotor inlet velocity profile and the effects of axial velocity ratio and secondary flow, achieved the design predicted performance. The corresponding tandem-blade stage (50-50% loading split in both blade rows) slightly exceeded the design pressure rise but was 1.5 percentage points low in efficiency. The tandem rotors tested during both phases demonstrated higher pressure rise and efficiency than the corresponding single-airfoil rotor, with identical inlet and exit airfoil angles

Single-stage experimental evaluation of tandem-airfoil rotor and stator blading for compressors. Part 1: Analysis and design of stages A, B, and C

A conventional rotor and stator, two dual-airfoil tandem rotors, and one dual-airfoil tandem stator were designed. The two tandem rotors were each designed with different percentages of the overall lift produced by the front airfoil. Velocity diagrams and blade leading and trailing edge metal angles selected for the conventional rotor and stator blading were used in the design of the tandem blading. Rotor inlet hub/tip ratio was 0.8. Design values of rotor tip velocity and stage pressure ratio were 757 ft/sec and 1.30, respectively

Single stage experimental evaluation of compressor blading with slots and vortex generators. Part 1 - Analysis and design of stages 4 and 5

Analysis and design of compressor blading with slots and vortex generator

Exchange Rates and the Competitiveness of the US Timber Sector in a Global Economy

This paper examines the competitiveness of the US timber industry under different exchange rate policies using a dynamic optimization model of global timber markets. We assume that exchange rates affect the cost structure of harvesting and managing forests and simulate the model for baseline conditions and four additional exchange rate policies. Two policies consider a strengthening United States dollar scenario and two policies examine weak South American currencies. Recently South America has increased its share of global timber production and is shipping increasing quantities of timber to the Unites States. The results indicate that US competitiveness in the forestry sector is sensitive both to strong US $policies and to the weak currency policies pursued by South American governments. A 20$ compared to all other currencies can reduce harvests by 4 7% in the United States over the next 50 years, while a similar reduction in currency values in South America can reduce U.S. production by around 0.4%. In dollar terms, each additional cubic meter of wood produced in South America due to currency policies can reduce producer surplus in the United States by $100.International Relations/Trade,

Assessing strength and power in resistance training

Maximal Dynamic Strength is usually assessed either by the one repetition maximum test (1-RM) or by a repetition maximum test with submaximal loads, which requires the application of a formula to estimate the value of 1-RM. This value is needed to establish the objective of resistance training: such as maximum strength, endurance strength, and/or explosive strength. However, both 1-RM and submaximal tests are unable to highlight the changes produced on power and velocity. This manuscript summarizes and reviews several common strength testing protocols and proposes a novel approach that may offer greater insight to hierarchical muscle functionalit