Although the interdisciplinary science of nanotechnology has been advanced significantly over the last few decades there were no closed-form analytical models to predict the three-dimensional (3D) boundary-layer-blockage (BLB) factor, of diabatic flows (flows involves the transfer of heat) passing through a nanoscale tube. As the pressure of the diabatic nanofluid and/or non-continuum-flows rises, average-mean-free-path diminishes and thus, the Knudsen number lowers heading to a zero-slip wall-boundary condition with the compressible viscous flow regime in the nano scale tubes leading to Sanal flow choking [PMCID: PMC7267099; Physics of Fluids, DOI: 10.1063/5.0040440] creating a physical situation of the sonic-fluid-throat effect in the tube at a critical-total-to-static pressure ratio (CPR). Herein, we presented a closed-form-analytical-model, which is capable to predict exactly the 3D-BLB factor at the Sanal flow choking-condition of nanoscale diabatic fluid flow systems at the zero-slip-length. The innovation of Sanal flow choking model in the nanoscale fluid flow system is established herein through the entropy relation, as it satisfies all the conservation laws of nature. The exact value of the 3D-BLB factor in the sonic-fluid-throat region presented herein for each gas is a universal benchmark data for performing high-fidelity in silico, in vitro and in vivo experiments for the lucrative design optimization of nanoscale fluid flow systems in gravity and microgravity environments and also for drug discovery for prohibiting asymptomatic cardiovascular diseases in Earth and human spaceflight <doi.org/10.2514/6.2021-0357>. Note that the relatively high and low-blood-viscosity (creating high turbulence) leads to the Sanal flow choking causing asymptomatic cardiovascular diseases. Such diseases in the cardiovascular system can be negated by maintaining the systolic-to-diastolic blood pressure ratio lower than the CPR <10.1002/gch2.202000076>. The CPR is regulated by the heat capacity ratio (HCR) of the fluid. Note that HCR is the key parameter, which could control simultaneously blood viscosity and turbulence. The physical insight of the boundary-layer-blockage persuaded nanoscale Sanal flow choking in diabatic flows presented in this article sheds light on finding solutions to numerous unresolved scientific problems in physical, chemical and biological systems carried forward over the centuries because the closed-form analytical model describing the phenomenon of Sanal flow choking is a unique scientific language of the real-world-fluid flows. More specifically, mathematical models presented herein are capable to forecast the limiting conditions of deflagration to detonation transition (DDT) in nanoscale systems and beyond with confidence. Additionally, the Sanal flow choking condition will forecast the asymptomatic-hemorrhage and acute-heart-failure https:/ /www.ahajournals.org/doi/10.1161/str.52.suppl_1.P804. Briefly, the undesirable Sanal flow choking causing detonation and hemorrhagic stroke can be negated by increasing the HCR of the fluid.