整流罩气动加热对红外成像系统像质的影响

Effect of pneumatic calefaction of the dome on IR imaging system quality

导弹高速飞行时,整流罩的气动加热会导致整流罩具有较高的温度,并且承受较大的气动载荷。利用ANSYS软件计算在500℃高温和4个大气压气动载荷下热压硫化锌红外平板窗口和同心球形整流罩的变形情况,并采用ZEMAX光学设计软件分析了变形对红外成像系统像质的影响。针对视场角13°、焦距70 mm、F数为1的红外长波成像系统进行了气动加热影响下的像质分析,结果表明:红外平板窗口的变形对成像系统所有视场的调制传递函数(16 lp/mm)几乎没有影响;同心球形整流罩的变形导致成像系统的调制传递函数最大下降了2.56%。

During the high speed flight of a missile,its dome was subject not only to high temperature, but also to load caused by pneumatic calefaction.In this work,the deform of both the planar window and the spherical dome made of ZnS material were ANSYS-based calculated at a temperature of 500℃ and at the pneumatic pressure of 4 atm.Furthermore,the effect of deform on IR imaging system quality were analyzed by ZEMAX optical design software.As to the IR long wavelength imaging system with optical parameters,field of view of 13°,focal length of 70 mm,and F number of 1,effect of pneumatic calefaction on imaging system quality was discussed.It has been demonstrated that the modulation transfer function（MTF）（16 lp/mm） in all field of view is insensitive to deform of IR planar window. However,deform of spherical dome could cause MTF declined by maximum 2.56%.