Designing a Firing Control System on S-60 57mm Cannon

The firing system on the S-60 57mm cannon uses the foot of the cannon crew, which is very dangerous with the position of the crew on top of the cannon when firing. So, a firing system that can be remotely controlled by a computer is required. The design of the S-60 57mm gun firing control system uses a personal computer (PC) as the firing command input, with data communication using WiFi received by the Atmega8535 microcontroller as a voltage regulator for solenoids. The solenoid has a tensile force to drive the hydraulic system where the actuator functions to drive the firing cylinder. Accelero sensor MMA7361, as a variable controller in firing, provides input data simulating the tilt position of the cannon, the position of the 0g sensor is simulated by the cannon in a balanced position. From the test results, there is a difference in sensor designation data with arc angles i.e., angle X by 2.83 degrees and angle Y by 1.86 degrees. The magnetic field produced by the solenoid 0.53 T can attract a maximum load of 20 kg. By changing the distance ratio of mechanical lever to 39.11 cm and 8.89 cm, the solenoid can drive an 88-kg firing cylinder.

Maximizing Injection Performance Through Fit-for-Purpose Dynamic Underbalance Perforation Using Unconventional Gun System in Offshore Well, Sarawak, Malaysia

The perforation strategy of Dynamic Underbalance (DUB) created the surging effect to remove debris from the perforation tunnels, thus reducing skin for optimal injectivity in this offshore development water injector well in Malay Basin, Offshore Sarawak. The objective was to inject up to 18,000 bwpd for pressure maintenance purposes. In the design phase, perforation software was used to perform the simulation iterations by sensitizing on the number of empty tubing conveyed perforation (TCP) gun chambers added at the top and bottom of perforation intervals. However, due to small gun size (4-½ in.), limited rat hole length and high static underbalance (1,000 psig), the desired amount of DUB using conventional empty gun volume only was not possible to be achieved. As a result, an innovative approach using two Pressure Operated Tester Valves (POTV's) was proposed, to create additional empty space inside the tubular between the POTVs above the packer. However, this created additional challenges which had to be overcome. Presence of empty tubulars in between the POTVs prevented the required hydraulic pressure transmission through the tubulars to activate the perforation guns via normal hydraulic TCP firing head. Therefore, a specialized firing system was required, which consisted of an acoustic communication system triggering downhole electronics to actuate a standard TCP firing head (Top-Fire Dual) - a first for this type of firing head. The POTV was activated by applying a pre-set annular pressure. Opening lower POTV, after the perforation fired, will create the required DUB surge, around 1,000 psi, which help cleaning up the perforation tunnels. Downhole fast gauges (recording in microseconds range) were run as part of the assembly to measure and to confirm the created DUB effect. Both fast gauges as well as acoustic gauges confirmed that 300 psi DUB was created upon gun firing and around 1,000 psi surging was achieved after the two POTVs were opened. Maximum losses recorded at 525 gallons per minute were observed following perforation. The well's injectivity performance was evaluated by performing step rate test and the result confirmed the well was able to meet higher injection rate than the plan.

Recoil Reduction Method of Gun with Side to Rear Jet Controlled by Piston Motion

Excessive recoil severely restricts the loading of high-power traditional guns on modern vehicles. To reduce the recoil without breaking the continuous firing mode and reducing the projectile velocity, a recoil reduction method that controls the lateral ejecting of propellant gas by a piston was proposed. The recoil reduction device is symmetric about the barrel axis. First, a one-dimensional two-phase flow model of interior ballistic during the gun firing cycle was established. Next, the MacCormack scheme was used to simulate, and the piston motion was gained. Then the propagation of the rarefaction wave in the barrel was presented. Finally, the propulsion difference between the piston-controlled gun and the traditional gun was discussed. The results showed that the recoil momentum was reduced by 31.80%, and the muzzle velocity was decreased by just 1.30% under the reasonable matching of structural parameters.

Numerical Calculation and Uncertain Optimization of Energy Conversion in Interior Ballistics Stage

Gun firing is a process that converts propellant chemical energy to projectile kinetic energy and other kinds of energies. In order to explore the energy conversion process, firstly, the interior ballistics mathematical model and the barrel-projectile finite element model are built and solved. Then, the related variable values and energy values are obtained and discussed. Finally, for improving energy efficiency, the interval uncertainty optimization problem is modeled, and then solved using the two-layer nested optimization strategy and back-propagation (BP) neural network surrogate model. Calculation results show that, after optimization, the heat efficiency raises from 31.13% to 33.05% and the max rifling stress decreases from 893.68 to 859.76 Mpa, which would improve the firing performance and prolong the lifetime of the gun barrel.

INTERNAL BALLISTICS OF CLASSIC GUN WITH COMPOSITE CHARGE

The paper presents a lumped parameter mathematical model considering the changes of thermodynamic properties for combustion products of a composite propelling charge, and of a burning cartridge casing or shell as well, when shot with classic guns. In addition a method was proposed for considering not coincidental instants of ignition for particular components of the charge and also for powder grains of each component, and the heat flow into the walls containing the space with combustion products. Some results of numerical computations are shown for 125 mm 2A46 tank gun firing a hard core projectile. Moreover an evaluation of accuracy of the results is given on the basis of experimental data. Maximum pressure and muzzle velocity were basic criteria at the verification of the model. Analysis of accuracy for solutions of model equations allows a conclusion that the proposed mathematical model may be useful at the designing process of ammunition and guns.