Numerical Investigation of a N₂O/HTPB Hybrid Rocket Motor with a Dual-Vortical-Flow (DVF) Design

Abstract

A compact hybrid rocket motor design that incorporates a dual-vortical-flow (DVF) concept is proposed. The oxidizer (nitrous oxide, N2O) is injected circumferentially into various sections of the rocket motor, which are sectored by several solid fuel “rings” (made of hydroxyl-terminated polybutadiene, HTPB) that are installed along the central axis of the motor. The proposed configuration not only increases the residence time of the oxidizer flow, it also implies an inherent “roll control” capability of the motor. Based on a DVF motor geometry with a designed thrust level of 11.6 kN, the characteristics of the turbulent reacting flow within the motor and its rocket performance were analyzed with a comprehensive numerical model that implements both real-fluid properties and finite-rate chemistry. Data indicate that the vacuum specific impulse (Isp) of the DVF motor could reach 278 s. The result from a preliminary ground test of a lab-scale DVF hybrid rocket motor (with a designed thrust level of 3,000 N) also shows promising performance. The proposed DVF concept is expected to partly resolve the issue of scalability, which remains challenging for hybrid rocket motors development.

Investigation of Dual-Vortical-Flow Hybrid Rocket Engine without Flame Holding Mechanism

“…The oscillation frequency based on numerical simulations is about 200 Hz which should be due to the lack of flame holding mechanisms in the reacting region near the disks. This oscillation is more distinct as compared to our previous work of DVF HRE with flame holders [10]. The reason without using flame holders as explained earlier is that the implementation of the flame holding mechanism becomes very difficult or even impossible due to the high temperature (exceeds 3000 K) in the reacting region with highly vibrating environment and the fuel shape (internal geometry) changes as it operates.…”

“…. These equations and models were discretized using the cellcentered finite-volume method, parallelized using MPI protocol and had been applied successfully to similar problems [10,12]. For the reacting species, the finite rate reaction model (a.k.a.…”

“…Arrhenius reaction model) was implemented. Together with a simplified set of species and reaction path [10], the UNIC-UNS code handles the species conservation equation. In general, the simulations were performed using a time step of 5 × 10 −6 s with boundary conditions summarized in Table 2.…”

“…All these studies are designed to meet specific requirement missions, such as large thrust for short period of time (boosters) and small thrust for long operation (cruising). Lai et al [10] recently proposed a highly efficient dualvortical-flow (DVF) engine. The overall performance of the proposed configuration may give a very stable and high efficiency combustion and thrust.…”

Thermodynamic properties calculations of Cu‐based species

“…The selection of copperbased materials is motivated by their wide applicability in catalysis domains, 24 such as material optimization, 25 which leads to improved functionality and performance. The aim is to convert thermochemistry data into thermodynamic coefficients that can be used in various applications of chemistry, physics, and engineering, such as combustion, [26][27][28][29][30][31] plasma modeling, [32][33][34] and atmospheric processes. [35][36][37] The acquired data and thermodynamic properties are then compared to experimental and previously calculated data.…”