7.
If the nose cone is anti-iced its hot air supply may be independent or integral with that of the nose cowl and compressor stators. For an independent system, the nose cone is usually anti-iced by a continuous
图13-3 热空气、滑油和电加温混合型防冰
Fig. 13-3 Combination of hot air, oil and electrical ice protection.
电加温系统统
9.电加温防冰系统一般用于涡轮螺桨发动机装置，因为，这种防冰形式是螺旋桨必需的。需要电加温的表面有发动机的进气道整流罩，螺旋桨桨叶和桨毂盖，如果可行的话，还包括滑油散热器进气道整流罩。
10.电加温垫粘接在整流罩的外蒙皮上。这些垫由夹在氯丁橡胶或浸渍环氧树脂的玻璃布层之间的条形导电层板组成。为了防止加温垫受到雨水腐蚀，在它的表面涂有特殊的在、聚氨基甲酸乙酯漆涂层。当除冰系统工作时，一些地方被连续加温以防止前缘处结成冰帽，同时限制那些断续加温地方的结冰程度（图13-4）。
11.电源由一发电机提供。为了将发电机的尺寸和重量限制在最小值，除冰用的电负载是在发动机、螺旋桨、有时还在飞机构件之间循环。
12.当防冰系统工作时，连续加温的地方防止任何冰的生产，但在断续加温的地方在不加温期间允许有冰生成。在加温时，粘附着的冰层破裂，然后被空气动力所驱散。
Ice protection
unregulated supply of hot air via internal ducting from the compressor.
8. The pressure regulating valves are electrically actuated by manual selection, or automatically by signals from the aircraft ice detection system. The valves prevent excessive pressures being developed in the system, and act also as an economy device at the higher engine speeds by limiting the air offtake from the compressor, thus preventing an excessive loss in performance. The main valve may be manually locked in a pre-selected position prior to take-off in the event of a valve malfunction, prior to replacement.
ELECTRICAL SYSTEM
9. The electrical system of ice protection is generally used for turbo-propeller engine installa-tions, as this form of protection is necessary for the propellers. The surfaces that require electrical heating are the air intake cowling of the engine, the 接线盒
断续加温元件
连续加温元件
电热元件
整流罩
玻璃布层
图13-4 电加温防冰
Fig. 13-4 Electrical ice protection.
propeller blades and spinner and, when applicable, the oil cooler air intake cowling.
10.
Electrical heating pads are bonded to the outer skin of the cowlings. They consist of strip conductors sandwiched between layers of neoprene, or glass cloth impregnated with epoxy resin. To protect the pads against rain erosion, they are coated with a special, polyurethane-based paint. When the de-icing system is operating, some of the areas are con-tinuously heated to prevent an ice cap forming on the leading edges and also to limit the size of the ice that forms on the areas that are intermittently heated (fig. 13-4).
11.
Electrical power is supplied by a generator and, to keep the size and weight of the generator to a minimum, the de-icing electrical loads are cycled between the engine, propeller and, sometimes, the airframe.
12.
When the ice protection system is in operation, the continuously heated areas prevent any ice
Ice protection
图13-5 显示的是一典型的循环顺序图。
Fig. 13-5 Typical ice protection cyclic sequence.
forming, but the intermittently heated areas allow ice to form, during their 'heat-off period. During the 'heat-on' period, adhesion of the ice is broken and it is then removed by aerodynamic forces.
13. The cycling time of the intermittently heated elements is arranged to ensure that the engine can accept the amount of ice that collects during the 'heat-off' period and yet ensure that the 'heat-on1 period is long enough to give adequate shedding, 14.通常采用双速度循环系统以满足螺旋桨和桨毂盖的需求；在空气温度较高时。通常水的浓度较大，可采用“快”速循环，较低温度范围下采用“慢”速循环。 中国航空网 www.aero.cn 航空翻译 www.aviation.cn 本文链接地址：劳斯莱斯喷气引擎－中英(77)
