Flowfield and Heat Transfer Characteristics of Cooling Channel Flows in a Methane-Cooled Thrust Chamber

Abstract

In recent years, methane has attracted attention as a propellant for liquid rocket engines because of its various advantages compared to typical propellants such as hydrogen. When methane is used as a coolant for a regenerative cooling system, its near-critical thermodynamic and transport properties experience large variations because its critical pressure is higher than that of typical propellants; this significantly influences the flowfield and heat transfer characteristics. Therefore, adequate understanding of the flowfield and heat transfer characteristics of methane in regenerative cooling channels is a prerequisite for future engine development. In this study, conjugated coolant and heat transfer simulations were performed to investigate the flowfield and heat transfer characteristics of transcritical methane flows in a sub-scale methane-cooled thrust chamber. The computed results were validated against experimental data measured in hot firing tests. They compared well with the measured pressures and temperatures in cooling channels, and wall temperatures were within the permitted levels. Detailed flow analysis revealed peculiar flow structures in the cooling channel: a strong secondary flow induced in the concave-heated part in the channel throat section and the coexistence of two different gas phases-ideal and real-in a single cross-section in the cylindrical region. A high wall temperature appeared in the cylindrical region of the thrust chamber under the considered conditions; this was due to the heat transfer deterioration induced by an M-shaped velocity profile and a turbulentheat flux reduction. Nomenclature a, b,  = coefficients in cubic-type equation of state C p = constant pressure heat capacity G = mass flow rate H = channel height h = heat transfer coefficient Pr = Prandtl number p = pressure q = heat flux R = gas constant Re = Reynolds number R u = universal gas constant s = normal distance T = temperature u = streamwise velocity W = molecular weight x, y, z = coordinate system Z = compressibility factor y + = normalized wall distance 2  = thermal conductivity  = viscosity  = density Subscripts b = bulk c = coolant cr = critical cw = coolant-side wall gw = hot-gas-side wall in = inlet out = outlet t = turbulent throat = throat pcr = pseudo-critical w = wall

Flowfield and Heat Transfer Characteristics in the LE-X Expander Bleed Cycle Combustion Chamber

“…2 that occur in the combustion chambers. [16][17][18][19][20][21][22][23][24] As a result, it was confirmed that CRUNCH CFD is an effective CFD tool to predict key physical phenomena in regeneratively cooled combustion chambers qualitatively and quantitatively. Furthermore, a conjugated combustion and heat transfer simulation methodology was recently proposed as a practical strategy that can model a full-scale combustion chamber and predict regenerative cooling performance.…”

Coupled Heat Transfer of Supercritical n-Decane in a Curved Cooling Channel

“…Most investigations implemented coupled heat transfer to simulate asymmetrically heated cooling channels because the temperature fields of the fluid region obtained with and without wall heat conduction are significantly different [2]. Previous studies showed that the selected geometries, fluids (hydrogen, nitrogen, methane), and boundary conditions were close to those expected in the regenerative cooling system of rocket engines (Froelich et al [3], Neuner et al [4], Jung et al [5], DiValentin and Naraghi [6], Kang and Sun [7], Pizzarelli et al [2,[8][9][10][11][12][13][14], Negishi et al [15], Ruan and Meng [16], and Wang et al [17]). A high aspect ratio cooling channel (HARCC) has been widely used in the regenerative cooling system of rocket engines.…”

“…As the fluid enters the curved section, the secondary flow streamlines obtained by the SA model and RSM become similar, that is, the flow is pushed against the concave wall near the channel midplane and pulled from the concave wall near the side wall (see15 and 45 deg cross sections of Fig. 7).…”

Effective Modeling of Conjugate Heat Transfer and Hydraulics for the Regenerative Cooling Design of Kerosene Rocket Engines

“…Before moving to the next downstream node, the coolant temperature increment by absorbing the heat flux and pressure losses due to friction and local flow resistances through the current channel segment are computed by Eqs. (15) and (17), respectively. Whenever the coolant temperature and pressure are updated, the thermophysical properties of the coolant are interpolated from the preconstructed lookup table, as mentioned in Subsection 2.4.…”

“…Kang and Sun [14] simulated the convective and radiative heat transfer of the hot gas, heat conduction within the channel, and the coolant flow in a regeneratively cooled rocket nozzle in a fully coupled manner to assess the modeling effects such as chemistry, radiation, and empirical correlations. Negishi et al [15] calculated conjugate heat transfer between coolant flow and heat conduction for a subscale methane-cooled thrust chamber with focus on the large property variation occurring in the transcritical flow. In their simulation, the computational grid system of about fifty millions is used for a circumferential half of the thrust chamber, including coolant manifolds, cooling channels, and chamber liners, while distribution of the wall heat flux on EFFECTIVE MODELING OF CONJUGATE HEAT TRANSFER 865 the hot-gas side is prescribed as thermal boundary condition from another hot-firing test with a calorimetric chamber.…”