Final answer:
The question seems to ask for calculations related to heat engines, such as efficiency, heat transfer rate, and overall heat transfer coefficient, but provides irrelevant parameters from hydrology (Unit Hydrograph). Without the correct data and context, it is not possible to compute these values. Therefore, the correct answer is option c) Find the overall heat transfer coefficient
Step-by-step explanation:
When analyzing the efficiency and heat transfer rates of a heat engine, we must first understand the given parameters and the necessary equations. The provided information refers to a triangular 1-hour Unit Hydrograph (UH) with a base time (Tb) of 12 hours and a rise time (Tr) of 4 hours.
However, in the context of thermal systems and heat transfer, the Unit Hydrograph figures appear to be unrelated. Since the information is not complete or relevant to the calculation of efficiency, heat transfer rate, or overall heat transfer coefficient for a heat engine, it is not possible to provide a direct answer.
In general, to calculate efficiency (Eff), the output work (W) is divided by the input heat (Qh), often expressed as Eff = W/Qh. For the heat transfer rate (Q/t), the amount of heat (Q) transferred over a certain time (t) is divided by that time.
Lastly, the overall heat transfer coefficient (U) is calculated by relating the heat transfer rate (Q/t) to the temperature difference across the medium (ΔT) and the area (A) through the formula Q/t = U*A*ΔT. It's important to have all the requisite data to perform these calculations properly.
As for calculating thermal efficiency in terms of heat transferred to the hot reservoir (Qh) and the cold reservoir (Qc), it can be mathematically expressed as Eff = (Qh - Qc) / Qh. To calculate the amount of heat transfer from a given quantity of heat Q and a turnover time t, the formula Q/t can be used to find the power or heat transfer rate. Without knowing the specific heat engine details or context for 'Tr' and 'Tb' in this scenario, it is not possible to perform the calculations otherwise indicated in the question.
Therefore, the correct answer is option c) Find the overall heat transfer coefficient