No abstract

Parametric design method of crankshaft is investigated in this study, based on the application of VB environment and CATIA secondary development of automation technology. Using the shape design parameters, the crankshaft can be established parametrically. The research results show that the proposed method can quickly generate crank shape, thus the repetitive operations can be decreased, and the costs can be saved.

The main geothermal resources in China are low or medium-temperature geothermal resources, these are more than 3000 hot springs, which of above 60 °C account for 24 percent of total, those are more than 720. In these hot springs bases for tourism and leisure and spa medical, the demand of electricity and air-conditioning is relatively large, so these is a very important practical significance to develop low or medium-temperature geothermal resources technology. If hot springs geothermal system uses lithium bromide-water azeotropic binary mixtures as working fluid, which not only reduces the heat loss of temperature difference, but also plays the advantages in thermodynamics and environmental aspects. Three systems of this article described all use water vapor as the working fluid, their characteristics are analyzed and compared, respectively. By analysis found that: when the demand is only for power generation and non-condensable gas content in hot springs geothermal water is not too high, the single-stage flash evaporation electrical system is more favorable; because of hot springs primarily for leisure travel and medical care function, and the demand for air conditioning and refrigeration is also large, so the combined system is more favorable.

Blade hydrofoil has a vital impact on efficiency of energy conversion of hydro turbine which is the core device in harnessing tidal current energy. In this paper, lattice Boltzmann method, combined with large eddy simulation (LBM-LES), where Smagorinsky model adopted, was proposed to simulate and analyze the performance of blade hydrofoil in tidal current flow with high Reynolds number in engineering application and solved the problem of instability when simulating flow with high Reynolds number using traditional lattice Boltzmann method. The results of simulation were verified by comparing with available experiment data and literatures.

The OTEC system of the paper studying is different with the traditional OTEC system, which takes the marine geothermal energy (black smokers) as the heat source, takes cold seawater of deep sea as the cold source. The paper analyzes and calculates some parameters of open-circle system which uses water vapor as the working fluid and the closed-circle system which uses pure ammonia as the working fluid, those parameters include thermal efficiency, heat load of condenser and evaporator, pump power consumption, and the net power output. The results show that: with the closed-circle system which uses pure ammonia as the working fluid, the large power consumption of hot water pump is the biggest problem for the open-circle system, besides reducing the temperature of hot fluid and increasing the flash pressure are disadvantageous for open-circle system; but water vapor as the working fluid helps to reduce the load of condenser and evaporator, which is very advantageous for heat exchanger design.