| The brightness of the tunnel lighting on transition section of high way tunnel should be changed toadjust the change of the brightness of outside. The output brightness of the fiber coupling lighting systemwill also changed with the change of solar illumination. According to this, the fiber coupling lightingsystem can be used for tunnel transition section lighting. The huge electricity bills and energy consumptiongenerated by electric lighting will be reduced. However, due to the influence of the low fiber coupling andtransmission efficiency, this technology cannot be used for real tunnel transition section lighting. Based onthese existed limitations, this paper analyzed every limiting conditions of the sunlight fiber-couplingsystem and designed a feasible system which can meet the requirements for tunnel lighting.In this paper, the features of sunlight and the theory of fiber-lighting is analyzed firstly. Then,analyzed the requirements for tunnel lighting, figured out the relationship between the brightness of insideand outside of the tunnel. Finally, concluded the available fiber coupling efficiency of the fiber couplingsystem which can meet the requirements for tunnel lighting. Fresnel lens was chose as the condensers forthe system after comparing and researching different kinds of condensers. Based on the analysis ofdifferent parameters and focusing properties of Fresnel lens, a combined lens group consisting of Fresnellens and convex lens was designed to enhance the coupling efficiency.After the analysis of the theory of the system, a simulation was conducted by using of ZEMAX,optimized the parameters of the combined lens group and finally got the detail parameters of the condenserwhich can meet the system requirements. From the result of the simulation, it proved that in the idealcondition, the focused sunlight can meet the needs of the tunnel lighting after it gets through the couplingsystem. Based on this, a further simulation and analysis on the impact of the angle of incidence of sunlightis conducted. And got the result when the system has some lateral offset, vertical offset, and angle offset.Then got the widest range of each offset that can meet system requirements. At last, a fiber optic lightingsunlight experimental platform was built and by the actual test, it proved that the coupling efficiency of theactual test system and the simulation is almost same. And furthermore, got the illuminance values at the50th m,100th m,150th m,200th m after the sunlight get though the fiber, and, these illuminances can meetthe requirement of brightness inside of the tunnel. That is to say, the designed fiber-coupling system can be used for tunnel lighting. The real experiment can also provide a reference for the system in the tunnellighting application. |
