| Indicated by the data from the2011Bureau of Ocean and Fishery of China, among all the fishing vessels,0.297million are motor fishing vessels and more than85%of all are smal scale wooden fishing boats, while90%of all are more than5years old and40%of all are more than10years old. The aging of fishing vessel certainly lead to a low energy efficiency of its engine and worsen the problem of high fuel consumption, which have become the biggest obstacle in modernization of fishery. Researches indicated that the efficiency of a diesel engine is normaly35%-40%and more than half of the energy is wasted as exhaust heat taken away by jacket water, cooling air and exhaust gas. Therefore, recovering energy from the exhaust heat has become an essential way for energy saving of fishing vessels.For a fishing vessel, the annual fuel consumption normally takes70%of the total fishery cost. In addtion to power the vessel engine, lots of energy are used to driven vapour compression refrigeration systems for air conditioning and ice making. Exhaust heat from a fishing vessel engine has been proposed to be used for direct heating. However, it could be utilizied in other useful forms, such as producing electricity, desalinating sea water, charging turbosand driving refrigeration systems. And due to the different system performance and application temperature ranges of various waste heat recovery techniques, different techniques should be selected according to both the characteristics of heat source and the daily life requirements aboard ships. A heat driven refrigeration system normally requires a heat source with medium temperature which can be as low as70℃, thus having a high potential to be combined with other techniques for the maximization of energy recovery efficiency. However, to improve the COP of heat driven refrigeration systems and ensure their operational stability under severe conditions on ocean are challengable. The concern of stability of refrigeration system onboard operation envoked the application of ejector refrigeration system, which has the advantage of stability and simple structure, for harvesting the exhaust heat from fishing vessel engine. This study focused on the stability of the mixed-refrigerants ejector refrigeration system driven by exhaust heat from fishing vessels and the main processes comes as follows:1. Make a analysis on each part of the mixed-refrigerants ejector refrigeration system to get the most important part which has a serious effect on the system stability upon ocean conditions.2. By building a mathematic model of the separator and using the CFD software, get a primary investigation of the influence of rolling and vibration conditions on the performance of the separator.3. Using a Three-degree Freedom Rolling Platform and several transparent tanks, observe the phenomena of the waves and slashing of water in the tanks directly upon different rolling conditions and quantitatively indicate the performance of mixed refrigerants in the real separator of ejector system.4. Using the Three-degree Freedom Rolling Platform and a real separator, analyze the effect of rolling and vibration on the separator and investigate the amount of liquid coming from its gas-outlet by experiment.5. Using the real separator with baffles, quantificational investigate the amount of water coming from its gas-outlet and analyze the damping of baffles on the fluid rolling and slashing in the separator to prepare for improving the performance of a separator in a mixed refrigerants ejector system used on the fishing vessels. |
PDF Full Text Request