Stratospheric Airship Roll Control for Solar Generator Overheating
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Solution Overview
Problem
Stratospheric airships equipped with solar generators face excessive heating due to insufficient forced convection, leading to potential damage and rupture of the solar generator and the balloon, as well as increased internal pressure, which existing thermal control methods fail to adequately address.
Innovation Solution
A stratospheric airship with a nonrigid balloon and a solar generator on its upper part, equipped with devices to manage the center of gravity and attitude, rotates by half a turn about its longitudinal axis when airspeed falls below a threshold or the solar generator temperature exceeds a threshold, to shield the solar generator from sunlight, using active or passive control systems to adjust the center of gravity and attitude.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If thermal control devices (exchangers and thermal protections) are installed on the solar generator, then the solar generator is protected from overheating, but the mass of the airship increases significantly
Solution Approach 1:
The patent extracts the thermal protection function from dedicated thermal control devices and relocates it to the airship's attitude control system. By rotating the entire airship to shield the solar generator from sunlight, the protection function is achieved without adding thermal control equipment, thereby eliminating the mass penalty while maintaining reliability.
Solution Approach 2:
The attitude control system, originally designed for stabilizing the airship's orientation, is given an additional function: thermal protection of the solar generator. By integrating both stabilization and protection functions into a single system, the patent avoids adding separate protection devices, thus preventing mass increase while ensuring reliable thermal management.
2Temperature
If the airship travels at higher speed to increase forced convection, then the solar generator is cooled effectively, but the energy consumption and operational constraints increase
Solution Approach 1:
The patent implements a dynamic protection strategy where the airship's orientation is adjusted in real-time based on operational conditions. When the airship is stationary or moving slowly (below threshold speed), it rotates to shield the solar generator from sunlight. This dynamic adaptation allows effective thermal management across varying speed conditions without being constrained by a minimum speed requirement.
Solution Approach 2:
The patent applies preliminary protection by proactively shielding the solar generator from sunlight before excessive heating can occur. The control system monitors speed and orientation, and when conditions indicate risk of overheating (low speed combined with sun exposure), the airship rotates to block sunlight in advance, preventing the harmful thermal effect rather than reacting after overheating begins.
3Use of energy by moving object
If the solar generator is exposed to sunlight for power generation, then energy is produced, but excessive heating occurs when forced convection is insufficient
Solution Approach 1:
The patent implements a feedback control mechanism that continuously monitors the airship's speed, orientation, and solar generator temperature. Based on this feedback, the control system dynamically adjusts the airship's orientation to balance power generation needs with thermal protection. When speed is sufficient for cooling, the solar generator is exposed to sunlight for power generation; when speed is low, the system rotates to shield the generator, preventing overheating while maintaining energy production capability.
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
This solution effectively prevents overheating of the solar generator, reduces thermal and mechanical stresses, and avoids damage to the airship by minimizing solar flux exposure and internal pressure increases, thereby enhancing the airship's robustness and operational flexibility.
Implementation Method 1
a solar generator arranged on the upper part of the nonrigid balloon intended to be illuminated in flight by the sun
Implementation Method 2
the speed of travel of the airship with respect to the surrounding air is below a first threshold above which thermal regulation by convection with the surrounding air prevents the solar generator, and therefore the balloon and its gas, from overheating
Data Source
AI summary
A stratospheric airship includes a nonrigid balloon equipped with a solar generator arranged on the upper part of the nonrigid balloon intended to be illuminated in flight by the sun, the airship comprising: at least one device for managing the position of the centre of gravity of the airship; at least one device for stabilizing the attitude of the airship; and a module for the coupled control of the devices, configured to control the airship, when the speed of travel of the airship with respect to the surrounding air is below a first threshold (S1) and/or the temperature of the solar generator is above a second threshold (S2), in such a way that it rotates by substantially half a turn about its longitudinal axis (AL), so as to protect the solar generator from illumination by the sun.