Thermal management and resistive rail heating of a large-scale naval electromagnetic launcher

Abstract

This paper presents a model that can be implemented to quickly estimate the resistive heating and the resulting transient temperature response. Quantifying the energy deposited in the rails and implementing an effective thermal management system will be key elements of an effective design for a large-scale electromagnetic launcher. The total current was divided between the inside, upper/lower and outside surface based on the results of a current distribution calculation. The diffusion of the magnetic field into each surface was modeled in order to determine the current distribution and the resistive heating. Cooling between shots was taken into account by solving the one dimensional transient heat diffusion equation within each surface. Repeating these calculations for a number of discrete segments down the length of the rail enabled the prediction of the total resistive rail heating and the temperature profile along the length of the rail. Experimental tests were conducted that verify the presence of localized heating in the corners of a U-shape conductor made of 7075 Aluminum. Taking into account the localized resistive heating near the surface of the conductor will become increasingly important with large-scale guns.

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

“…Naval Academy,Mechanical Engineering Department,Annapolis,MD,21402-5000 8. PERFORMING ORGANIZATION REPORT NUMBER…”

“…The temperature dependence of the resistivity of the rail material was taken into account, along with thermal diffusion occurring within the current pulse. It has been previously shown that it is necessary to account for thermal diffusion during the current pulse [8]. Table I.…”

“…The resistance of the launcher changes with time as the projectile physically moves down the barrel and the magnetic field diffuses into the rail. Several investigations have been performed using an analytical approach [5], segmented rail with an effective height [6]- [7], segmented rails where the magnetic field diffuses into multiple surfaces [8], and full three dimensional simulations of the launcher [9]. In this paper, an effective height model is used to simulate the transient rail resistance based on the method presented by Parker et al [7].…”

“…It was assumed in this simulation that only the launcher resistance varied with time. The resistance of the launcher was determined using an effective height model based on a 135mm square bore [6]- [8]. In order to calculate the effective height, the non-uniform surface current profile around the perimeter of the rail cross-section must be calculated.…”

Dynamic Response of Electromagnetic Launcher’s Rail Subjected to Cosine Pressure

“…With the development of new technology and new material, the research of launcher, launching weight, projectile velocity and high efficiency power source in the electromagnetic rail gun have reached a series of achievement in recent years. By 2002, the United States and Brigade had cooperated to launch projectile weighted 3 ~ 4kg to a initial velocity of 3km/s with power of 32MJ capacitor bank (Smith A N, 2005, Fair H D, 2005and Sympathy S S, 2004. Other countries have also made great progress in studying of the electromagnetic technology.…”