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
圖13-3 熱空氣、滑油和電加溫混合型防冰
Fig. 13-3 Combination of hot air, oil and electrical ice protection.
電加溫系統統
9.電加溫防冰系統一般用于渦輪螺槳發動機裝置，因為，這種防冰形式是螺旋槳必需的。需要電加溫的表面有發動機的進氣道整流罩，螺旋槳槳葉和槳轂蓋，如果可行的話，還包括滑油散熱器進氣道整流罩。
10.電加溫墊粘接在整流罩的外蒙皮上。這些墊由夾在氯丁橡膠或浸漬環氧樹脂的玻璃布層之間的條形導電層板組成。為了防止加溫墊受到雨水腐蝕，在它的表面涂有特殊的在、聚氨基甲酸乙酯漆涂層。當除冰系統工作時，一些地方被連續加溫以防止前緣處結成冰帽，同時限制那些斷續加溫地方的結冰程度（圖13-4）。
11.電源由一發電機提供。為了將發電機的尺寸和重量限制在最小值，除冰用的電負載是在發動機、螺旋槳、有時還在飛機構件之間循環。
12.當防冰系統工作時，連續加溫的地方防止任何冰的生產，但在斷續加溫的地方在不加溫期間允許有冰生成。在加溫時，粘附著的冰層破裂，然后被空氣動力所驅散。
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 接線盒
斷續加溫元件
連續加溫元件
電熱元件
整流罩
玻璃布層
圖13-4 電加溫防冰
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
圖13-5 顯示的是一典型的循環順序圖。
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.通常采用雙速度循環系統以滿足螺旋槳和槳轂蓋的需求；在空氣溫度較高時。通常水的濃度較大，可采用“快”速循環，較低溫度范圍下采用“慢”速循環。 中國航空網 m.k6050.com 航空翻譯 www.aviation.cn 本文鏈接地址：勞斯萊斯噴氣引擎－中英(77)
