Condenser Add-Heat Valve Control for Aircraft Ice Removal
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The existing environmental control systems on aircraft face challenges with icing in condensers, particularly when ambient temperatures are below freezing and there is excessive ram air flow, as the on/off valve lacks sufficient thermal capacity to maintain the condenser inlet temperature above freezing.
Innovation Solution
An icing control system with a selectively movable add heat valve that taps hot air downstream of the compressor and directs it to the condenser and second stage turbine, allowing for controlled heating to prevent icing by positioning the valve in one of three configurations based on ambient temperature and ram air flow conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the on/off valve is used to add hot air to the condenser inlet, then the condenser inlet temperature is raised to prevent freezing, but the valve lacks sufficient thermal capacity when there is excessive ram air flow
Solution Approach 1:
The add heat valve is divided into three distinct positions (first position blocking flow, second position passing air through condenser to turbine, third position passing air only to condenser) to provide segmented thermal capacity control. This segmentation allows the system to deliver hot air selectively to the condenser inlet with greater thermal capacity than the conventional on/off valve, ensuring reliable icing prevention even when excessive ram air flow is present.
Solution Approach 2:
The valve position parameter is changed from a binary state (open/closed) to a three-state configuration, enabling continuous adjustment of hot air flow quantity to the condenser. This parameter change allows the system to match the thermal capacity of added hot air to the specific icing risk conditions, effectively raising the condenser inlet temperature above freezing point under various operating conditions.
2Power
If the add heat valve passes hot air to both the condenser and second stage turbine, then thermal capacity is increased, but the heating effect at the condenser inlet may be insufficient when only condenser heating is needed
Solution Approach 1:
The third position of the add heat valve segments the flow path to direct hot air exclusively to the condenser inlet, separating the heating function from the turbine feed function. This segmentation enables precise control where the full thermal capacity of the hot air can be applied to the condenser without being diluted by mixing with turbine inlet air, ensuring adequate heating effect even when excessive ram air flow is present.
Solution Approach 2:
The valve positioning enables local quality control by directing hot air to specific locations based on system needs. In the third position, hot air is directed locally to the condenser inlet with maximum concentration and thermal capacity, providing focused heating where needed without affecting the turbine inlet temperature, thus achieving both high thermal capacity and precise heating control.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Effectively prevents icing in the condenser by providing controlled heating to the condenser inlet, ensuring the temperature remains above freezing even under conditions of excessive ram air flow and low ambient temperatures.
Implementation Method 1
the valve only communicates air from the tap passage into the condenser
Implementation Method 2
Effectively prevents icing in the condenser by providing controlled heating to the condenser inlet, ensuring the temperature remains above freezing
Implementation Method 3
the air flows through an environmental control system that decreases the air temperature by means of exchanging heat through the heat exchangers in a ram air flow circuit
Implementation Method 4
exchanging heat through the heat exchangers in a ram air flow circuit
Implementation Method 5
The conditioned air then flows through a condenser to condense the moisture out of the air stream to provide a comfortable dry air source to the cabin environment
Data Source
AI summary
Environmental control system bleed air is cooled by a heat exchanger. A fan pulls ambient air from a ram inlet duct across the at least heat exchanger and to an outlet. An air cycle machine drives the fan. The bleed air passes downstream of the at least heat exchanger to a compressor, and then drives a first stage turbine. The first stage turbine has an outlet communicating with a condenser, and then a second stage turbine. An icing control system taps hot air downstream of the compressor. An add heat valve is selectively moveable between a first position blocking flow from the tap passage. A second position where it passes air from the tap passage to the condenser inlet, and to a point downstream of the condenser and to the second stage turbine. In a third position, the valve only communicates air from the tap passage into the condenser.