A system having an impingement sleeve configured to receive a cooling flow is provided. The impingement sleeve includes a column of ports extending from an outer surface of the impingement sleeve, wherein each port of the column of ports is configured to direct an impingement stream toward a heated structure, and each impingement stream includes a portion of the cooling flow. Further, one or more pins are disposed outside the outer surface relative to the cooling flow, wherein each pin of the one or more pins is coupled between pairs of ports of the column of ports.