Heat Generation During the Firing of a Capacitor-Based Railgun System

Abstract

Abstract-Railguns use a high-current, high-energy electrical pulse to accelerate projectiles to hypersonic velocities. Pulse forming networks that employ capacitors as the energy store are typically used to shape the required electrical pulse. A significant fraction of the stored energy (25 -40% in large caliber railguns) is converted to projectile kinetic energy during launch. After the projectile exits the launcher, the balance of the energy has either been dissipated as heat in the circuit components or is stored in system inductance. If an energy recovery scheme is not employed, the inductor energy will also be dissipated in the resistance of the active circuit components. A circuit analysis has been performed in order to calculate the current profile from the PFN. A higher fidelity solution was achieved by accounting for the temperature dependent resistance of the rails. This information along with individual component resistance and inductance was used to calculate the distribution of energy subsequent to a single pulse. Detailed component heating information is important when considering the overall thermal management of the system. Once this information has been obtained, the components that require external cooling can be identified, and an appropriate thermal management system can in turn be designed.

Three-dimensional launch simulation and active cooling analysis of a single-shot electromagnetic railgun

“…Combining equations (8), (11), (12), (15) and (16) together, the equation for the magnetic vector potential has the form…”

“…The current that passes through the rails exerts an electromagnetic force (Lorentz force) on the armature and causes it to accelerate to high speeds. 9 Previous studies [10][11][12] showed that for a conceptual pulsed-power system working with total energy loads larger than 155 MJ, approximately 37% (~26 MJ) of the total energy is dissipated as heat in the rails and armature. The remaining energy dissipates among the other system components:~43% as kinetic energy in the projectile, 9% in the muzzle shunt, and~11% in the capacitors, switches, diodes, inductors and cables.…”

Application based general scaling in railguns

“…The original scale gun parameters were loosely based on a proposed 160 MJ gun [9] while the scaled version's gun length, inductance gradient, resistance, and energy were chosen arbitrarily. The other scaled parameters such as projectile speed and mass were calculated using the scaling laws in Table 2.…”

Mathematical formulation and demonstration of a dynamic system-level ship thermal management tool

“…System-level thermal analysis of an all-electric ship is an essential procedure during its early design stages for devising effective thermal management strategies, to satisfy ship cooling requirements in all conceivable operation modes and scenarios. In an all-electric ship, devices integrated for control, power, propulsion, and weaponry are predicted to dissipate considerable amounts of heat [1][2][3][4][5]. In [3][4][5], the authors report the notional pulsed weapon system, radar, and vital loads (e.g.…”

“…In an all-electric ship, devices integrated for control, power, propulsion, and weaponry are predicted to dissipate considerable amounts of heat [1][2][3][4][5]. In [3][4][5], the authors report the notional pulsed weapon system, radar, and vital loads (e.g. sensors, data processors, etc.)…”